delivered the opinion of the Court.

Complainants, as judgment creditors, sued White, an insolvent non compos mentis, and his guardian and Dyer County, seeldng to subject an alleged indebtedness of the County to White on account of unpaid salary accruing while he served out an unexpired term as County Trustee.

A vacancy having occurred in the office, a number of parties became candidates before the County Court, and that Court undertook to exact an agreement from the candidates that the salary of the office for the balance of the unexpired term should be reduced from $5,000' per annum fixed by the general salary law to $2,500 per an-num. It appears that White made this stipulation and was elected. The day he qualified he had a serious injury and was never thereafter physically or mentally in condition to perform the duties of the office, but the office was conducted without complaint by his wife and his deputies. As guardian for White, his wife was paid the salary of the office on the reduced basis of $2,500.

The theory of the bill is that the County still owes to White the difference between the $5,000 annual salary' fixed by the general law and the amount paid, $4,166.66, *34 this difference being on the $2',500' basis, and the bill seeks to recover from the County the amount of the debt of the complainants ag’ainst White, in the snm of $1,886.34.

The Chancellor dismissed the bill, holding that White was estopped and that his creditors were likewise es-topped by the agreement referred to under which he took office. The Court of Appeals has reversed, holding that such an agreement was contrary to public policy and would not be given recognition, in application of the doctrine of estoppel, or otherwise, and awarded judgment. We approve the conclusion of the Court of Appeals and a petition filed herein for certiorari is denied.

Counsel for petitioner here rely upon Saylor v. Trotter, 148 Tenn., 359, 373, 255 S. W., 590, and also upon an unpublished opinion of Mr. Justice McKinney in Webb v. Roberts 1 et al., from Blount Equity, which opinion followed the Saylor Case in principle.

In Saylor v. Trotter, supra, and in several unreported cases arising under the general salary law, Chapter 101, Pub. Acts of 1921, Code sections 10725, et seq., among them Webb v. Roberts 1 , supra, this Court has applied es-toppel to officials affected by this legislation. In other cases application of estoppel has been denied, for example, Ha ys Clark v. Hamilton County, 1 (March, 1935) and Hamilton County v. Burns, 1 December term 1937. It is apparent that some misapprehension exists as to the principles governing and the distinctions recognized in these decisions.

The underlying determinative distinction was clearly set forth in the opinion of Chief Justice G-been in the leading case of Saylor v. Trotter, supra, at page 373, 255 S. W., at page 594, as follows:

*35 “We are not unmindful of State ex rel. v. Mayor, etc., of Nashville, 83 Tenn. (15 Lea), 697, 54 Am. Rep., 427, and the decisions upon which, it rests; State ex rel. v. Purdy, 36 Wis., 213, 17 Am. Rep., 485; State ex rel. v. Collier, 72 Mo., 13, 37 Am. Rep., 417; Carrothers v. Russell, 53 Iowa, 346, 5 N. W., 499, 36 Am. Rep., 222; Alvord v. Collin, 20 Pick. (Mass.), [418], 428.

“In these cases candidates promised to remit all or part of the salaries to which they were entitled hy law, if elected. Such agreements were held to be against sound policy, as a sort of bribery of the public by candidates for office — a purchase of office by promises of money or services or both. Practices like these tend toward the selection of the lowest bidder among the candidates regardless of his merit.

“The case before us is entirely different. The candidate here only expressed his purpose to do what the act required. This was his legal and moral duty as long as the act remained in force. He did not propose to donate or give up to the county anything, but only proposed to be satisfied with the compensation and perform the duties of the office upon the terms which the Legislature had fixed.

“We think the public interest will not be jeopardized by raising an estoppel, as we have done, against an officer who has assented to an act of the Legislature, prescribing his duties and his compensation, in a case where only his individual profit and convenience are at stake. ’ ’

The case now before us comes directly within the class described in the second paragraph of the foregoing quotation, — being one of that class in which ‘ ‘ candidates promised to remit all or part of the salaries to which they were entitled by law, if elected.” In the *36 Saylor Case, and otters in wtict ttis Court tas applied estoppel, tte candidate tad “only expressed tis purpose to do wtat tte act required.” Ttere was an act of tte Legislature wtict was prima facie constitutional, in effect and binding upon tim. Our toldings tave been, in effect, ttat one taving’ recognized and teld timself out as willing to serve under tte terms thereof, would not be beard thereafter to attack its validity and repudiate its terms. Tte situation ttus arising is clearly to be distinguished from one in wtict, in tte teeth of an unchallenged statute, a candidate agrees to remit a part of tte salary fixed by ttat law in case of tis election. It is a well settled principle of public policy ttat a public officer cannot make a valid agreement to ttis effect, and tte promise being void, estoppel will not be applied. 22 R. C. L., pages 537, 538, and cases cited, among otters our case of State v. Nashville, 83 Tenn. (15 Lea), 697, 54 Am. Rep., 427, referred to and approved in tte above quotation from tte opinion in Saylor v. Trotter, supra. Said Judge Coopeb, in State v. Nashville, “If a candidate makes suet a promise to tte voters, it is only binding in tte forum of conscience. It may impose upon tim a moral, but no legal obligation. If an office tave a salary attached to it, it is even against public policy to permit suet agreements. Ttis has been determined in numerous cases,” citing several.

Where, as in tte Blount County.and otter unreported cases, tte official after acquiescing in and accepting benefits under an act, files tis suit attacking its constitutionality, te has been teld to be estopped by tis previous recognition and acknowledgment of its validity.

Ttis is not tte case now before us. No act had been passed by tte Legislature and no law was existent fixing *37 or attempting to fix the salary of this office in Dyer .County at $2',500, or any other amount less than that fixed by the general salary law. The agreement made by White herein shown is, therefore, directly within the general rule, approved in Saylor v. Trotter, supra, holding such attempted agreements void, to which estoppel is inapplicable. This was the conclusion reached by the Court of Appeals in which we concur. Petition for certiorari is denied.