Where is the boundary between 'new claims,' whose default federal habeas courts may excuse, and 'new facts,' which federal habeas courts may not consider under Cullen v. Pinholster when applying 28 U.S.C. § 2254(d)?

QUESTION PRESENTED CAPITAL CASE Petitioner presented a federal district court with allegations and evidence that counsel had been ineffective at sentencing on the basis of facts and legal theories that he had not presented previously in state court. If Petitioner presented new “claims” in federal court, he would have the opportunity to show cause and prejudice for any default under Martinez v. Ryan, 566 U.S. 1 (2012). On the other hand, if he simply presented new “evidence” to supplement the claims of ineffectiveness that the state court previously had adjudicated on the merits, the federal court could not consider that evidence under Cullen v. Pinholster, 563 U.S. 170 (2011). Pinholster did not specify how habeas courts should determine whether petitioners have proffered new claims or new evidence in support of claims. Lower courts trying to draw that distinction have approached their task with varying fidelity to this Court’s pre-Pinholster precedent, which holds that a federal proffer in support of a claim makes that claim a “new” one, subject to the doctrine of procedural default, if it “fundamentally alter[s]” a claim made in state court. See Vasquez v. Hillery, 474 U.S. 254, 260 (1986). The question presented is: Where is the boundary between “new claims,” whose default federal habeas courts may excuse, and “new facts,” which federal habeas courts may not consider under Cullen v. Pinholster when applying 28 U.S.C. § 2254(d)? 1