Order

The judgment of the district court dismissing Sperberg’s petition under 28 U.S.C. § 2241 for want of jurisdiction is incompatible with Collins v. Holinka, 510 F.3d 666 (7th Cir. 2007), which holds that a prisoner’s use of the one collateral attack allowed under 28 U.S.C. § 2255(h) does not deprive a district court of subject-matter jurisdiction to entertain a later petition under § 2241. Whether the proceeding is allowable under § 2255(e) is a question on the merits; it does not affect subject-matter jurisdiction. Compare In re Davenport, 147 F.3d 605 (7th Cir. 1998), with Taylor v. Gilkey, 314 F.3d 832 (7th Cir. 2002).

On remand, the district court should reconsider its decision in light of Estrada v. Holder, 604 F.3d 402 (7th Cir. 2010), and the position asserted in the brief for the respondent warden filed in this court on May 24, 2010. We leave to the discretion of the district court whether it is appropriate to appoint a lawyer to serve as amicus curiae in support of the position that this *603 situation is covered by Taylor rather than Davenport.