What is the test for a writ of habeas?

principle to the facts of the prisoner's case. Williams v. Taylor, 529 U.S. 362, 405-06 (2000). A federal habeas court "may not issue the writ simply because that court concludes in its independent judgment that the relevant state-court decision applied clearly established federal law erroneously or incorrectly. Rather, that application must also be unreasonable." Id. at 411.