The Supreme Court ruled Monday that state rape-shield laws may bar evidence of past consensual sexual relations between the alleged attacker and victim.

By a 7-2 vote, the justices ordered further lower court hearings that could lead to reinstatement of the sexual assault conviction of Nolan Lucas of Michigan, charged with attacking his former girlfriend.Justice Sandra Day O'Connor, writing for the court, said the rights of an accused rapist are not violated automatically by excluding evidence of his past sexual relationship with the purported victim.

At issue in Lucas's case is whether evidence of his relationship with his former girlfriend may be barred from the trial because Lucas failed to notify prosecutors within 10 days after his arraignment that he would seek to introduce such evidence.

The 10-day rule "serves legitimate state interests in protecting against surprise, harassment and undue delay," O'Connor said.

In other action, the court:

- Struck down the death sentence of Bryan Lankford, an Idaho killer, ruling 5-4 that he and his lawyer had inadequate warning that the sentencing judge was considering the death penalty.

- Ruled that the National Institutes of Health should not have been allowed to transfer a lawsuit by animal rights groups from state to federal court, where it was dismissed.

- Rejected a Nevada challenge to the federal government's efforts to put a high-level nuclear waste dump at Yucca Mountain, about 100 miles northwest of Las Vegas.