WASHINGTON — The Supreme Court announced Friday that it will rule on a crucial — and fiercely debated — element of President Bush’s legal strategy in the war against terrorism: his assertion of authority to declare U.S. citizens captured on American soil "enemy combatants" and detain them indefinitely without charges or access to counsel.

In a brief order, the justices said they would hear the Bush administration’s appeal of a ruling by a federal appeals court that invalidated the president’s June 2002 decision to detain as an enemy combatant Jose Padilla, a U.S. citizen arrested in Chicago on suspicion of involvement in an al-Qaida bomb plot. The justices outlined an expedited briefing schedule that would enable them to hear the case by the last week of April and decide it by July.

Though expected, the court’s decision nonetheless has dramatic implications.

Now, all the elements are in place for a series of Supreme Court rulings this spring that will define the power of the commander in chief during wartime — and bring an election-year climax to the national debate over civil liberties and public safety that has been simmering since the terror attacks of Sept. 11, 2001.

The Padilla case, Rumsfeld v. Padilla, No. 03-1027, joins a companion case already granted by the court in which a U.S.-born Saudi national captured as an alleged Taliban fighter in Afghanistan is challenging the president’s authority to designate him as an enemy combatant. The court is also scheduled to hear an appeal by more than a dozen foreign alleged al-Qaida and Taliban detainees at the Guantanamo Bay Naval Base who claim they have a right to seek their freedom in federal court.

Padilla’s case has been the focus of controversy since he was arrested May 8, 2002, upon his return from Pakistan to Chicago’s O’Hare International Airport. A former street-gang member with a homicide conviction in his juvenile record, Padilla had converted to Islam and used the name Abdullah al Muhajir during travels to Egypt, Saudi Arabia and Afghanistan.

U.S. officials had developed intelligence linking him to al-Qaida; his return to the country was believed to be related to al-Qaida plans to detonate a radioactive "dirty bomb" within the United States.

Initially, the government held Padilla as a material witness, and a public defender was assigned to represent him. But on June 9, 2002, just before a deadline by which the Justice Department would have had to either charge Padilla or release him, Bush signed an order declaring him an enemy combatant and ordered him sent to a Navy brig in South Carolina. He has been held there ever since, without access to a lawyer until recent weeks.