It takes four votes on the U.S. Supreme Court to take a case by granting certiorari. The U.S. Supreme Court declined to do so in the case of Jose Padilla today. It was considered eight times by the Justices. Three of them filed a dissenting opinon saying that they would have granted certiorari (Ginsberg, Breyer and Souter). An unusual concurring opinion joined by Roberts, Kennedy and Stevens refused to grant certiorari, on quasi-mootness grounds, while expressing concern about the government's actions in the case. Justices Alito, Thomas and Scalia were silent.
The opinion of the U.S. Court of Appeals for the 4th Circuit, which upheld Padilla's detention and accepted the government's argument more or less completely, remains the only binding valid precedent on the issue.
On the whole, it remains a bad day for civil liberties, although it is possible that the case will resurface with a happier result at a later time.