28 U.S.C. § 2251: Stay of State court proceedings

A justice or judge of the United States before whom a habeas corpus proceeding is pending, may, before final judgment or after final judgment of discharge, or pending appeal, stay any proceeding against the person detained in any State court or by or under the authority of any State for any matter involved in the habeas corpus proceeding. For purposes of this section, a habeas corpus proceeding is not pending until the application is filed. If a State prisoner sentenced to death applies for appointment of counsel pursuant to section 3599(a)(2) of title 18 in a court that would have jurisdiction to entertain a habeas corpus application regarding that sentence, that court may stay execution of the sentence of death, but such stay shall terminate not later than 90 days after counsel is appointed or the application for appointment of counsel is withdrawn or denied. After the granting of such a stay, any such proceeding in any State court or by or under the authority of any State shall be void. If no stay is granted, any such proceeding shall be as valid as if no habeas corpus proceedings or appeal were pending. This section [enacting section 2265 of this title , amending this section and sections 2261 and 2266 of this title, and repealing former section 2265 of this title ] and the amendments made by this section shall apply to cases pending on or after the date of enactment of this Act [ Mar. 9, 2006 ]. In a case pending on the date of enactment of this Act, if the amendments made by this section establish a time limit for taking certain action, the period of which began on the date of an event that occurred prior to the date of enactment of this Act, the period of such time limit shall instead begin on the date of enactment of this Act.”