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  There is a very high bar for excusing a prisoner’s failure to develop the state-court record. Shortly before AEDPA, we held that a prisoner who “negligently failed” to develop the state-court record must satisfy Coleman’s cause-and-prejudice standard before a federal court can hold an evidentiary hearing. Keeney v. Tamayo-Reyes, 504 U. S. 1, 9, 112 S. Ct. 1715, 118 L. Ed. 2d 318 (1992). In Keeney, the court explained that “little [could] be said for holding a habeas petitioner to one standard for failing to bring a claim in state court and excusing the petitioner under another, lower standard for failing ...