The men's plight has posed a dilemma for the Bush administration and courts. Previously, a federal judge said the detention of the ethnic Uighurs in Guantanamo Bay is unlawful, but that there was nothing federal courts could do.
Lawyers for the two contend they should be released, something the Bush administration opposes, unless they can go to a country other than the United States.
A year ago, the U.S. military decided that Abu Bakker Qassim and A'Del Abdu al-Hakim are not "enemy combatants" as first suspected after their 2001 arrests in Pakistan. They were captured and shipped to Guantanamo Bay along with hundreds of other suspected terrorists.
The U.S. government has been unable to find a country willing to accept the two men, along with other Uighurs. They cannot be returned to China because they likely will be tortured or killed.
German officials are being pressed to take them, according to a report over the weekend in a newspaper there.
It would have taken an unusual intervention of the Supreme Court to deal with the case now.
Lawyers for Qassim and al-Hakim filed a special appeal, asking justices to step in even while the case is pending before an appeals court. Arguments at the U.S. Court of Appeals for the District of Columbia Circuit are next month.
Justices declined, without comment, to hear the case.
Bush administration Supreme Court lawyer Paul Clement told justices that there were "substantial ongoing diplomatic efforts to transfer them to an appropriate country."
Clement said that in the meantime, the men have had television, a stereo system, books and recreational opportunities: including soccer, volleyball and ping-pong.
The detainees' lawyers painted a different picture, saying that hunger strikes and suicide attempts at Guantanamo Bay are becoming more common and that the men are isolated.
"Guantanamo is at the precipice," Boston lawyer Sabin Willett wrote in the appeal. "Only prompt intervention by this court to vindicate its own mandate can prevent the rule of law itself from being drowned in this intensifying whirlpool of desperation."
About 500 foreigners are being held at Guantanamo Bay. Lawyers for more than 300 of the men filed a brief in Monday's case, saying that Qassim and al-Hakim "are far from the only innocent non-combatants languishing at Guantanamo."
Justices ruled two years ago that the detainees could use American courts to challenge their detentions. And the court this summer will rule on a case testing President Bush's plans to hold war-crimes trials at Guantanamo Bay.
Qassim and al-Hakim were captured as they fled a Taliban military training camp where they were learning techniques they planned to use against the Chinese government. They are Uighurs, Turkic-speaking Muslims who have a language and culture distinct from the rest of China.
The case is Qassim v. Bush, 05-892.