Whether a habeas petitioner who seeks a Rhines stay to exhaust a claim of ineffective assistance of counsel must establish a 'reasonable probability of a different outcome' in order to establish that his claim is not 'plainly meritless'

QUESTIONS PRESENTED I. Whether a habeas petitioner who seeks a Rhines stay to exhaust a claim of ineffective assistance of counsel must establish a “reasonable probability of a different outcome” in order to establish that his claim is not “plainly meritless.” In particular, whether applying such an exacting merits-based standard runs afoul of this Court’s rule that a petitioner need only establish a “colorable claim” in order to justify a Rhines stay, as well as the federalism and comity principles underlying it. II. Whether a certificate of appealability may be a mere “rubber stamp,” or whether it should issue where the district court’s ruling differs from the opinions of other courts on complex procedural issues that have not been squarely addressed by this Court.