¶1 Today we must decide whether the Washington Constitution requires that a jury be seated to determine the issues presented in a probable cause hearing commenced pursuant to RCW 71.05.240, a mental illness statute. We hold that it does not. Because no jury was required and because substantial evidence supports the trial court’s findings of fact, we affirm. 1

I

¶2 S.E. was involuntarily committed to Fairfax Hospital for an initial period of evaluation and treatment due to concerns about her dangerous mental disorder. An evaluating physician from Fairfax petitioned the superior court to authorize an additional 14 days of commitment to allow for further evaluation and treatment of S.E.

¶3 At the resulting probable cause hearing, the superior court determined by a preponderance of the evidence that S.E., due to a mental disorder, presented a significant risk of serious harm to others and that she was gravely disabled. The superior court granted the petition, authorizing 14 days of additional commitment for evaluation and treatment.

¶4 S.E. now appeals.

II

A

¶5 Washington’s statutory scheme regulating the involuntary detention of those persons suspected of suffering *612 from a dangerous mental illness was enacted in 1973. Codified at chapter 71.05 RCW, the statutory scheme provides for various lengths of detention for evaluation and treatment and designates various decision-makers.

¶6 The initial detention period provided for is 72 hours. RCW 71.05.150, .180. For this detention period to commence, a designated mental health professional must first receive and investigate allegations that a person, “as a result of a mental disorder,” “presents a likelihood of serious harm” or “is gravely disabled.” RCW 71.05.150(l)(a). 2 If the mental health professional is satisfied as to the truth of the allegations and determines that the person will not voluntarily seek treatment, the professional may submit a petition to the superior court seeking authorization for a 72-hour commitment period for evaluation and treatment. RCW 71.05.150(1). Thereafter, upon review of the petition, the superior court may—in an uncontested determination— issue an order to detain the person if the judge is satisfied that probable cause supports the petition and that the person has refused or failed to voluntarily accept appropriate evaluation and treatment. RCW 71.05.150(2)(a).

¶7 Thereafter, if further commitment is warranted, the evaluating professional can petition for another 14 days of commitment. RCW 71.05.230. After a 14-day petition is filed, the superior court must—within 72 hours of the person’s initial detention—hold a proceeding referenced as a probable cause hearing. RCW 71.05.240(1). At the probable cause hearing, the petitioner must show, by a preponderance of the evidence, that the person identified in the petition, “as the result of mental disorder, presents a likelihood of serious harm, or is gravely disabled.” RCW 71.05.240(3)(a). Although the probable cause hearing is adversarial, the statutory scheme does not provide for a right to a jury determination of the question whether the *613 person’s mental disorder warrants 14 additional days of commitment.

¶8 If commitment beyond the first 17 days—the initial 72-hour period followed by the 14-day period—is sought, the evaluating professional may petition for 90 or 180 days of further commitment for treatment. RCW 71.05.280, .290. Notably, upon the filing of a 90- or 180-day petition, the statutory scheme provides for a right to demand that a jury determine whether the person’s mental disorder justifies the lengthier commitment period requested. RCW 71.05-.310. Thereafter, a contested proceeding occurs wherein the superior court or, if demanded, a jury determines whether the petitioners have shown by clear, cogent, and convincing evidence that the commitment is justified by the person’s mental illness pursuant to the statutory grounds tailored to the lengthier commitment period requested. See RCW 71-.05.310, .320(1).

¶9 If the evaluating professional determines that further commitment beyond the 90- or 180-day period is necessary, a petition seeking a further 180-day commitment may be filed. RCW 71.05.320(4). Thereafter, another contested proceeding is held—pursuant to the procedures set forth in RCW 71.05.310—and the superior court or a jury must find that the additional commitment is warranted pursuant to distinct statutory grounds tailored to the 180-day commitment request. RCW 71.05.320(6)(a). If further 180-day periods of commitment are sought, petitions are filed and heard in the same manner as provided in RCW 71.05.320(4).

B

¶10 S.E. calls our attention to a territorial statute that was in effect in 1889. This statute provided the subject of an insanity trial with the right to a jury trial on the question of whether the person was sane or insane. This, by itself, S.E. argues, establishes that—at the time of statehood—no *614 person could be detained for any period of time based on a belief that the person was insane without first having had a jury determine the person’s insanity. On this premise, S.E. contends that RCW 71.05.240 is unconstitutional because it does not provide a person the right to a jury determination of the issues presented at a probable cause hearing. S.E.’s argument in this regard also constitutes an implied challenge to RCW 71.05.150, inasmuch as the 72-hour commitment period provided for therein is also allowed to commence without a jury first determining the factual question of the person’s sanity.

C

¶11 We review de novo a constitutional challenge to a statute, with a presumption that the statute is constitutional. In re Det. of M.W., 185 Wn.2d 633, 647, 374 P.3d 1123 (2016) (citing City of Bothell v. Barnhart, 172 Wn.2d 223, 229, 257 P.3d 648 (2011)). As the party challenging the constitutionality of a statute with regard to the jury trial right, S.E. bears the burden to show that territorial authority in effect upon the adoption of the Washington Constitution provided for a right to a jury trial in a proceeding analogous to the challenged statutory proceeding. M.W., 185 Wn.2d at 647, 662 (citing Barnhart, 172 Wn.2d at 229; Endicott v. Icicle Seafoods, Inc., 167 Wn.2d 873, 884, 224 P.3d 761 (2010)).

¶12 The Washington Constitution provides that “ [t] he right of trial by jury shall remain inviolate.” Const. art. I, § 21. 3 In proceedings to commit a person for evaluation and treatment of a mental disorder, “the jury plays an essential role in guarding against wrongful commitment.” In re Quesnell, 83 Wn.2d 224, 241, 517 P.2d 568 (1973).

*615 ¶13 To determine whether the state constitution grants the right to a jury trial in a particular proceeding, we engage in a two step analysis: “First, we determine the scope of the right to a jury trial as it existed at the time of our founding in 1889; second, we determine if the type of action at issue is similar to one that would include the right to a jury trial at that time.” M.W., 185 Wn.2d at 662 (citing Endicott, 167 Wn.2d at 884). The nature of our inquiry “ ‘is a purely historical question, a fact which is to be ascertained like any other social, political or legal fact. The right is the historical right enjoyed at the time it was guaranteed by the Constitution.’ ” Wings of the World, Inc. v. Small Claims Court, 97 Wn. App. 803, 807, 987 P.2d 642 (1999) (internal quotation marks omitted) (quoting State ex rel. Goodner v. Speed, 96 Wn.2d 838, 841, 640 P.2d 13 (1982)). 4

¶14 We look to contemporaneous legal authority as well as legal authority subsequent to statehood as representative of “the essence of the [jury trial] right’s scope.” Sofie v. Fibreboard Corp., 112 Wn.2d 636, 645-46, 771 P.2d 711, 780 P.2d 260 (1989) (referencing In re Ellern, 23 Wn.2d 219, 224, 160 P.2d 639 (1945) and State v. Strasburg, 60 Wash. 106, 116, 110 P. 1020 (1910)); see also Speed, 96 Wn.2d at 841-42 (discussing State v. Tieman, 32 Wash. 294, 295-98, 73 P. 375 (1903)).

D

¶15 S.E. asserts that, at the time of statehood, no person could be detained for any period upon suspicion of insanity unless such detention was preceded by a court hearing at which a jury could decide the facts. She has not proved this to be true.

*616 ¶16 “[W]hatever right may have been given to a trial by jury in proceedings to adjudicate insanity by a territorial statute, a constitutional guaranty that the right to trial by jury shall remain inviolate preserves such right to the extent given by the statute ” Sherwin v. Arveson, 96 Wn.2d 77, 83, 633 P.2d 1335 (1981) (emphasis added) (citing Ellern, 23 Wn.2d at 224).

¶17 In commitment proceedings, the jury trial right was preserved “[i]nasmuch as the Code of 1881, § 1632 . . . provided that when the mental condition of a person was the subject of judicial inquiry, he had the right to demand a jury trial.” Sherwin, 96 Wn.2d at 83.

¶18 Section 1632 of the Code of 1881 read:

The probate court of any county in this territory, or the judge thereof, upon application of any person under oath, setting forth that any person by reason of insanity is unsafe to be at large, or is suffering under mental derangement, shall cause such person to be brought before said court or judge at such time and place as the court or judge may direct; and shall cause to appear at said time and place, one or more respectable physicians who shall state under oath in writing, their opinion of the case, which opinion shall be carefully preserved and filed with the other papers in the case; and if the said physician or physicians shall certify to the insanity or idiocy of said person, and it appear to the satisfaction of the court or judge that such is the fact, said court or judge shall cause such insane or idiotic person to be taken to and placed in the hospital for the insane in Washington territory:[ 5 ] Provided, That such person or any person in his behalf, may demand a jury to decide upon the question of his insanity, and the court or judge shall discharge such person if the verdict of the jury is that he is not insane.

Code of 1881, ch. 110, § 1632, at 277.

*617 ¶19 The plain text of § 1632 makes clear that the jury trial right attached to the trial before the probate court at which the question of the person’s insanity was decided. The statute provided for a single contested trial, envisioning one proceeding in which witnesses—“one or more respectable physicians”—were called to evaluate and testify as to the person’s insanity. If found insane, the person was committed to the “hospital for the insane” for an indefinite period. It was to this type of proceeding that the jury trial right attached.

¶20 A probable cause hearing held pursuant to RCW 71.05.240 is not a proceeding of the same type. Its differences will be discussed below.

¶21 Moreover, at its core, S.E.’s contention is that—in territorial days—no person could suffer a loss of liberty without first having a jury decide the facts necessary to justify such a commitment. But S.E. does not prove this to be so. And history belies the contention.

E

¶22 S.E. next asserts that, in territorial days, the right to a jury trial attached to any proceeding akin to the probable cause hearing referenced in RCW 71.05.240. She does not prove this to be so.

¶23 In fact, our review of the relevant statutes and cases reveals no indication that a jury trial was required before a person accused of insanity could be detained for up to 17 days. Indeed, there was no territorial proceeding akin to the probable cause hearing provided for in RCW 71.05.240.

1

¶24 The second inquiry necessary to determine whether the constitutional jury right applies is whether the action at issue is similar to one that included a jury trial right in 1889. M.W., 185 Wn.2d at 662. This “inquiry is not whether *618 the specific cause of action existed in 1889, but rather whether the type of action is analogous to one available at that time.” Endicott, 167 Wn.2d at 884 (citing Sofie, 112 Wn.2d at 648-49).

¶25 The challenged statute reads, in pertinent part:

Petition for involuntary treatment or alternative treatment—Probable cause hearing. ... (1) If a petition is filed for fourteen day involuntary treatment..., the court shall hold a probable cause hearing within seventy-two hours of the initial detention or involuntary outpatient evaluation of such person as determined in RCW 71.05.180.[ 6 ] . . .

(3) At the conclusion of the probable cause hearing:

(a) If the court finds by a preponderance of the evidence that such person, as the result of mental disorder, presents a likelihood of serious harm, or is gravely disabled .. ., the court shah order that such person be detained for involuntary treatment not to exceed fourteen days.

RCW 71.05.240.

¶26 The probable cause hearing is an adversarial proceeding at which the party seeking the commitment of another must present a preponderance of the evidence to support its petition. No right to a jury trial is provided for either the initial 72-hour detention period or the 14-day commitment period. 7 RCW 71.05.150, .240(4). A superior court judge determines whether the petition requesting commitment is properly supported. RCW 71.05.150(2)(a), *619 .240(3)(a). When a petition is filed requesting further commitment for treatment beyond the first 17 days of detention—the 14-day period following the initial 72-hour period—a right to a jury trial is provided. RCW 71.05.310.

¶27 In this way, the probable cause hearing set forth by RCW 71.05.240 features an adversarial proceeding wherein a judge—rather than a jury—decides whether, by a preponderance of the evidence, a person’s mental illness justifies a cumulative detention period of up to 17 days.

¶28 S.E. must therefore prove that—in 1889—a jury trial right was provided in a proceeding akin to the probable cause hearing set forth in RCW 71.05.240.

2

¶29 There is no indication in our territorial or early statehood authority that a jury was required to decide whether a person’s suspected insanity justified detaining the person for up to 17 days. In fact, available authority suggests that, in 1889, persons suspected of suffering from insanity were often subject to being detained without prior jury authorization for up to 60 days or more.

a

¶30 As mentioned, the territorial probate court was accorded jurisdiction over civil proceedings concerning persons suspected of insanity. Code of 1881, ch. 110, § 1632, at 277. The jury trial right attached to the proceeding set forth in § 1632—the insanity trial. The trial on the person’s insanity occurred when the territorial probate court convened in open court. 8 In 1889, the probate court convened every 60 days. Code of 1881, ch. 95, § 1301, at 232.

*620 ¶31 Prior to the insanity trial, the person was subject to being detained upon a determination by the probate court— rather than a jury. We can see that this was so given that a prerequisite for the insanity trial was a determination by the probate court that the person named in the petition, “by reason of insanity [,] is unsafe to be at large, or is suffering under mental derangement.” Code of 1881, ch. 110, § 1632, at 277. In addition, the Code of 1881 authorized the probate court to act as a conservator of the peace with authority to arrest and detain persons who were suspected of being dangerously insane. Code of 1881, ch. 95, § 1309, at 233. This authority included the authority to cause a peace officer to detain the individual. 9

¶32 But nowhere do these provisions suggest that—in 1889—there was provided a right to have a jury determine whether the facts alleged in the commitment petition justified an insanity trial or whether the person should be involuntarily detained as part of being “caused” to appear before the court at the time of trial. Rather, the territorial statutes suggest that in 1889, a person accused of insanity *621 could be detained for at least 60 days without first having a jury decide whether the deprivation of liberty was justified. S.E. makes no attempt to prove otherwise.

b

¶33 Enactments by our legislature from early statehood reinforce this view. In 1915, the state legislature passed a bill regulating the preliminary commitment period for observation of a person charged with insanity. The law read, in pertinent part:

PRELIMINARY COMMITMENT AND OBSERVATION OF PERSONS CHARGED WITH INSANITY.

An Act relating to the insane, their preliminary care and commitment, and providing for an observation detention ward in county hospitals.

Be it enacted by the Legislature of the State of Washington:

Section 1. There shall be set aside in each county in the State of Washington having a county hospital, such portions of such hospital as may be necessary for observation detention wards for those charged with insanity, and in each such hospital there shall be separate detention wards for males and females, and any judge of the superior court[ 10 ] of the State of Washington before whom a person is charged with insanity may order the sheriff arresting said person to forthwith commit such person to said observation detention ward for a period, not to exceed thirty (30) days, except as hereinafter provided: .... Said detention wards shall be under the supervision and control of the county physician of the county in which situated, who shall make careful observation of the patients under his charge and testify at the trial of the patient as to such observation, and should *622 said physician require longer time for observation of said-patient than thirty days, he shall make application to the court for an extension of time of not more than thirty days.

Laws of 1915, ch. 105, at 303-04 (emphasis added); see also Rem. Comp. Stat. § 6931. Pursuant to this statute, the superior court was authorized to commit a person charged with insanity to a “detention ward” for a period not to exceed 60 days—30 days plus an additional 30 days, if requested. The statute did not provide a right to demand a jury trial. Thus, 26 years after statehood, the 1915 legislature did not require that a jury determine whether a person’s suspected insanity justified up to 60 days of detention.

¶34 In 1951, nearly four decades later, the legislature repealed the 1915 provision and enacted a similar provision in its place, which read:

There shall be set aside in each county of the state of Washington having a county hospital, such portions of such hospital as may be necessary for the detention and observation of those persons detained under the provisions of this act pending further proceedings. In each such hospital there shall be separate detention wards for males and females. The superior court may order the examination of such persons by medical personnel for the purpose of obtaining testimony as to the alleged- mentally ill person’s condition. Such observation period shall not exceed- sixty days unless a jury trial has been demanded.[ 11 ]

Laws of 1951, ch. 139, § 28, at 350 (emphasis added). This provision, like its predecessor, set forth a preliminary period of detention of up to 60 days. This provision, too, did not provide for a jury to decide whether a person’s suspected insanity justified the 60-day detention period.

¶35 Thus, the 1915 and 1951 legislatures each enacted a law authorizing a person charged with insanity to be *623 detained for up to 60 days without also providing for a jury to decide whether the detention was justified. This suggests that such detention, without jury involvement, upon a suspicion of insanity was considered to be consistent with historical practice. S.E. offers no historical perspective to the contrary.

c

¶36 Furthermore, a 1945 opinion by our Supreme Court is instructive on the question of whether—in 1889—a jury was required to decide whether a person’s suspected insanity justified a pretrial period of detention. In Ellern, the factual exposition read, in part:

The material allegations of the petition, in so far as are necessary for a determination of the case, are that on February 15, 1944, the petitioner was taken into custody by reason of a complaint made against him by his wife, Bernice Ellern, charging him with being an insane person and dangerous to be at large; that his attorney made and filed a demand in writing that the question of his insanity be determined by a jury; that this demand was ignored by the trial judge; that he was not present when the hearing was had to determine his mental condition; that on July 11,1944, he was declared by the superior court of Washington for Pierce county to be sane and not dangerous to be at large, and was discharged from custody.

23 Wn.2d at 221 (emphasis added). These facts show that Ellern was charged with insanity and subsequently detained for almost five months. Ellern, 23 Wn.2d at 221.

¶37 If, at statehood, a jury decision was constitutionally required before a person suspected of insanity could be subject to pretrial detention, there is a curious absence of objection or reference to this constitutional right in an opinion filed 55 years after statehood and 72 years prior to today.

¶38 It is notable that our Supreme Court, at a time so much closer to initial statehood and in an opinion concern *624 ing the jury trial right in insanity proceedings, did not find it significant that Ellern was detained, without jury approval, while awaiting trial on a charge of insanity. This suggests that such detention was consistent with historical practice. And, more to the point, S.E. does not prove otherwise.

d

¶39 S.E. fails to prove that—in 1889—a person suspected of insanity could not be detained while awaiting trial on the sanity question. Instead, the territorial and early statehood authority suggest that, without a jury’s decision regarding whether such detention was justified, a person suspected of suffering from insanity could be detained for up to 60 days without controversy.

3

¶40 Next, S.E. must prove that there was a proceeding in 1889 akin to the probable cause hearing set forth in RCW 71.05.240. S.E. does not prove this to be so.

¶41 As described above, § 1632 of the Code of 1881 set forth a proceeding for a person suspected of insanity in 1889. This statute authorized the territorial probate court, upon its satisfaction of the facts alleged in the commitment petition, to order an insanity trial. Code of 1881, ch. 110, § 1632, at 277. As analyzed herein, the probate court also had authority to order that the person be detained until the trial. Code of 1881, ch. 95, § 1309, at 233; Code of 1881, ch. 110, § 1632, at 277. A jury trial right was provided for the insanity trial and one or more physician witnesses were required to attend and testify. Code of 1881, ch. 110, § 1632, at 277. Section 1632 mentioned neither a proceeding referenced as a probable cause hearing nor any other adversarial proceeding occurring before the insanity trial.

¶42 From 1889 to 1973, commitment proceeding legislation retained many of the features established at law in *625 1889. The legislature continued to authorize the superior court to review commitment petitions and order an insanity trial. Laws of 1959, ch. 25, § 71.02.090, at 81-82; Laws of 1951, ch. 139, § 17, at 346-47; Laws of 1889, ch. 16, § 16, at 486. The legislature repeatedly authorized the superior court to detain persons suspected of insanity for up to 60 days prior to trial. Laws of 1959, ch. 25, § 71.02.120, .130, at 82-83; Laws of 1951, ch. 139, § 18, at 347, § 28, at 350; Laws of 1915, ch. 105, § 1, at 303-04; Const, art. XXVII, § 10. 12 The legislature provided for a right to demand a jury for the insanity trial. Laws of 1959, ch. 25, § 71.02.210, at 86; Laws of 1951, ch. 139, § 23, at 348; Laws of 1889, ch. 16, § 16, at 486. And the legislature consistently provided for physicians as witnesses at the trial. Laws of 1959, ch. 25, § 71.02.170, at 85; Laws of 1951, ch. 139, § 21, at 348; Laws of 1889, ch. 16, § 16, at 486.

¶43 In 1973, our legislature enacted a new statutory scheme for commitment proceedings. The legislature’s hope was to “prevent inappropriate, indefinite commitment of mentally disordered persons.” RCW 71.05.010(l)(b). The 1973 statutory scheme adopted some features of the earlier commitment statutes but sought to provide greater protections to those accused of suffering from a dangerous mental illness.

¶44 Significantly, the legislature provided for an adversarial proceeding, referenced as a probable cause hearing, to result upon a petition for commitment for treatment for 14 days. RCW 71.05.230, .240. As discussed, the petitioner was required to meet a burden of proof at the probable cause hearing and show by a preponderance of the evidence that the person named in the petition was dangerously mentally ill, pursuant to RCW 71.05.240.

*626 ¶45 This probable cause hearing was a novel addition to Washington’s commitment procedure. There is no indication that, in 1889, prior to the insanity trial, there had been any adversarial proceeding that placed a burden of proof on the petitioner in response to a petition for short-term commitment. Indeed, as mentioned, the territorial statutes suggest that the procedure for commitment included a nonadversarial judicial review of the facts alleged in the commitment petition, a nonadversarial judicial determination that the person should be detained pending trial, and a later insanity trial (to which the jury trial right attached). Clearly, none of these territorial procedures contained features analogous to those of the probable cause hearing referenced in RCW 71.05.240, an adversarial proceeding with a specified burden of proof.

¶46 Thus, S.E. does not prove that a proceeding existed in 1889 akin to the probable cause hearing set forth in RCW 71.05.240. 13

4

¶47 Finally, as a practical matter, S.E.’s contention that—in 1889—jury trials on the sanity question must have been held within three days of initial detention 14 is plainly implausible. Ninety years ago, our Supreme Court acknowledged the travel conditions and described the effort exerted to travel to the seat of government in territorial days:

The framers of the constitution must have had in mind the conditions which then existed. This was then a territory about *627 to be admitted into the sisterhood of the states. It was traversed from east to west by but one line of railroad. Many . . . coming from the northeasterly and the southeasterly portions of the new state might and would have to travel many miles by stage or private conveyance before they could reach a line of railway, and then perhaps four hundred or more miles of railway travel to reach the seat of government. Days would be consumed in the journey.

State ex rel. Banker v. Clausen, 142 Wash. 450, 455, 253 P. 805 (1927).

¶48 Similarly, the framers of our constitution must have had in mind the conditions that existed regarding the practical exercise of the jury trial right in 1889. These conditions plainly were not conducive to the rapid conveyance of physician witnesses and jurors. In 1889, even when no jury trial was demanded, abundant notice and travel time were likely required simply to arrange for an insanity trial to take place. Further, when a jury trial was demanded, even greater coordination and advance preparation would be required, this time to garner 12 men to sit as jurors—even more so during planting or harvesting season or in far-flung, sparsely populated rural counties throughout the territory.

¶49 S.E. does not attempt to show that, given the territorial travel conditions, it was so that jurors were seated within 72 hours of a person’s detention so that they could decide whether a person’s suspected insanity justified keeping the person in continued detention. Our study of relevant authority reveals no suggestion that this was historically so.

5

¶50 Thus, there was no proceeding in 1889 to which the jury trial right attached akin to the proceeding referenced as a probable cause hearing in RCW 71.05.240. Accordingly, the Washington Constitution does not require that a jury be *628 seated to determine the issues presented in a probable cause hearing commenced pursuant to RCW 71.05.240.

¶51 The remainder of this opinion has no precedential value. Therefore, it will be filed for public record in accordance with the rules governing unpublished opinions. See RCW 2.06.040.

Review denied at 189 Wn.2d 1032 (2018).