Two years after the newly minted Obama administration moved to undo what had become one of the most controversial legacies of the George W. Bush presidency by ordering the closure of the prison camps at Guantánamo Bay, Cuba, a trove of State Department documents is providing new information about why that effort failed.

Key among the factors, the cables suggest: Congress' refusal to allow any of the captives to be brought to the United States.

In cable after cable made public by the website WikiLeaks, American diplomats make it clear that the unwillingness of the United States to resettle a single detainee in this country -- even from among 17 ethnic Muslim Uighurs considered enemies of China's communist government -- made other countries reluctant to take in detainees.

Europe balked and said the United States should go first. Yemen at one point proposed the United States move the detainees from Cuba to America's SuperMax prison in the Colorado Rockies. Saudi Arabia's king suggested the military plant micro-chips in Guantánamo captives before setting them free.

A January 2009 cable from Paris is a case in point: France's chief diplomat on security matters insisted, the cable said, that, as a precondition of France's resettling Guantánamo captives the United States wants to let go, ``the U.S. must agree to resettle some of these same LOW-RISK DETAINEES in the U.S.'' In the end, France took two.

Closing the Guantánamo detention center had been a key promise of the Obama presidential campaign, and new President Barack Obama moved quickly to fulfill it.

Just two days after taking the oath of office, on Jan. 22, 2009, Obama signed an executive order instructing the military to close Guantánamo within a year. European countries were effusive in their praise.

But as the second anniversary of that order passed Saturday, the prison camps remained open, and the prospects of their closure appeared dim. Prosecutors are poised to ramp up the military trials that Obama once condemned, and the new Republican chairman of the House Armed Services Committee, Rep. Buck McKeon of California, last week said the United States should grow the population to perhaps 800 from the current 173.

WHAT WENT WRONG

Many factors worked to thwart Obama's plans to close the camps -- from a tangled bureaucracy to fears that released detainees would become terrorists. But Congress' prohibition on resettling any of the detainees in the United States hamstrung the administration's global search for countries willing to take the captives in.

The U.S. refusal to take in the captives ``comes up all the time,'' acknowledged a senior Obama administration official of U.S. efforts to find homes for released detainees.

``Were we willing to take a couple of detainees ourselves, it would've made the job of moving detainees out of Guantánamo significantly easier,'' said the official, who agreed to speak only anonymously because of the delicacy of the diplomacy.

Still, the Obama administration has managed to arrange to find new homes for 38 Guantánamo detainees in 16 countries, including Bermuda, Bulgaria, Palau and Portugal.

Why?

Some countries found the individual stories of men at Guantánamo with no place to go ``compelling,'' the official said. ``Some wanted to help the United States in general. Some wanted to help Obama in particular.''