WASHINGTON: After embarrassing false starts, Barack Obama is making a final push to close Guantanamo prison, but to fulfill that glaringly incomplete campaign promise he faces unpalatable compromises and internal resistance.

When Congress returns from recess in September, Obama's top counter-terror adviser Lisa Monaco and Defense Secretary Ash Carter will submit a fresh plan to shutter the infamous 13-year-old facility.

As a candidate and as US president, Obama promised to close Guantanamo, arguing indefinite detention, "enhanced interrogation" and images of caged men in orange jump suits violated America's ethos and handed militants a potent recruiting tool. But ensconced in the Oval Office, he quickly became ensnared in a legal and political thicket.

Six years on, with the clock running down on his presidency, Obama will take another crack.

Read: Obama renews vow to close Guantanamo detention camp

The plan, which is now virtually complete, would lift Congressional restrictions on transferring detainees to the United States.

The administration is looking at military facilities like Fort Leavenworth, Kansas or the Navy Brig in Charleston, South Carolina as possible destinations for inmates. That may raise objections from hostile local politicians.

But a more substantial roadblock might be the fate of future terror captives and as few as a dozen of the 116 inmates now at Guantanamo deemed too dangerous to release but too difficult to prosecute.

Already critics are warning that Obama's proposals to amend preventive detention cannot allow a category of indefinite detainees in an indefinite war on terror. That would mean Guantanamo is being moved rather than closed.

"You can't simply change the zip code at Guantanamo and expect that to solve the human rights problem or erase the stain that Guantanamo has left on the United States' reputation," said Naureen Shah of Amnesty International.

But in return for having Congressional restrictions lifted, Obama will have to deal. Senator John McCain, who opened the door to Obama's plan being heard by Congress, backs Guantanamo's closure, but wants guarantees inmates will not be given more rights than they already have.

Specifically, the senator — who himself was bayoneted, bound and tortured during five years as a prisoner of the war in Vietnam — wants to make sure that once transferred to the United States, legal machinations will not win an inmate release.

The Obama administration may decide that some form of extended preventive detention may be a price worth paying to be able to close the facility.

Take a look: Dentention in Guantanamo: Obama eats his words

Internal divisions

Still, the fate of the remaining bulk of prisoners has exposed divisions within the administration that may yet make closing Guantanamo impossible on Obama's watch.

The plan is expected to quicken the pace of hearings for those inmates who are not among the 52 already approved for transfer. But even those approved have languished. All but nine of them are from Yemen, which is now in the throes of a civil war.

"No one is going to send individuals to Yemen right now," said Cliff Sloan, a former special envoy for Guantanamo closure at the State Department.

But, he insists, that should not prevent a more rapid whittling down of detainees at Guantanamo, with many allies expressing a willingness to help.

"We should be seeing transfers every month," he told AFP. "There should be a sense of urgency."

The particular fate of two men already approved for transfer has led to allegations that Obama's Department of Defense has been dragging its heels, even after a row that contributed to Pentagon boss Chuck Hagel's exit.

Tariq Ba Odah, a Yemeni currently on hunger strike, has been cleared for release since 2009. Sources familiar with deliberations inside the administration say the Department of Defense is concerned his release may encourage or reward similar hunger protests.

And despite a request from London, the Department of Defense has also been reluctant to release Shaker Aamer, allegedly over concern about what he may reveal about operations at Guantanamo.

Publicly, the White House insists "the President's entire national security team is working together to fulfill the President's steadfast commitment to closing the Guantanamo detention facility."

The Pentagon says Guantanamo must be closed in a "responsible manner that protects our national security."

"A decision to approve a detainee for transfer does not reflect a decision that the detainee poses no threat or no risk of recidivism," said Commander Gary Ross, a Pentagon spokesman.

Even if all this is resolved, Obama faces an election-season political battle to get the Republican controlled Congress to back, or at least not scuttle, the deal.

After Obama's political victories in reaching a nuclear deal with Iran, trade with Asia, health care, gay rights and re-establishing diplomatic relations with Cuba, few would bet against the outgoing president.

But Guantanamo, one of the first items on his desk when he took office, may yet remain one of the last when he leaves.

Also read: US transfers six Guantanamo detainees to Oman