An Army captain walks outside unoccupied detainee cells inside Camp 6 at the U.S. detention center at Guantanamo Bay, Cuba, on Feb. 6, 2016. The White House is expected to deliver a plan to Congress to shutter the facility by a Tuesday deadline. (AP Photo/Ben Fox)

The Obama administration on Tuesday sent Congress its plan to close the Guantanamo Bay military prison, but the move will likely do little to help the president keep his campaign promise to shutter the controversial detention facility.

The long-awaited plan delivered few surprises. It contains revised estimates about the cost of transferring the detainees currently at Guantanamo to the United States, and a rundown of how closing the facility could save taxpayers money. Such estimates were expected to be delivered to Congress last year, but the plans were delayed after the president rejected the Pentagon’s earlier calculations.

Congress has also asked the administration to include in the plan information about where and how the administration intends to hold existing and future detainees, if Guantanamo is closed.

Regardless of the details, numerous political and legal challenges remain between Obama delivering Congress a game plan to shutter the facility and actually getting it done.

“I am very cleared eyed about the hurdles to closing Guantanamo,” Obama said when unveiling his proposal Tuesday morning. “The politics of this are tough.”

Chief among those hurdles is the fact the government has used Guantanamo for over 14 years to hold suspected terrorists, and most members of Congress don’t want to see those prisoners brought to the United States.

Though the administration has been steadily resettling detainees in various countries – last month, the Guantanamo population dropped below 100 for the first time since 2002 – U.S. transfers are almost certainly necessary to shut down the detention facility entirely. That fact has sparked fears among members of Congress that the president might go around the legislature and try to close Guantanamo by executive action if they don’t endorse his plans.

With that in mind, lawmakers have taken several steps to ensure that the administration cannot shutter Guantanamo without their express permission. The most critical of these steps is a provision of the law barring the president from using any funds to transfer detainees to the United States, or construct or modify any facilities in the United States to house them.

In the past, the administration has hedged when asked whether Obama would try to close Guantanamo by executive action if Congress refused to approve his plans.

But last week, Lt. Gen. William Mayville, director of the Joint Staff at the Pentagon, wrote in a letter to 16 members of Congress that the military had no intention of going around the prohibition on transferring detainees.

Despite supporting Obama’s goal of closing Guantanamo, “the Joint Staff will not take any action contrary to those restrictions,” Mayville wrote in a letter sent to Rep. Mike Pompeo (R-Kan.), one of 16 lawmakers who received similar correspondence.

That leaves the administration with just the token opening that Congress gave it last year as part of the current National Defense Authorization Act.

Under that law, Congress gave the secretary of defense, the attorney general and the director of national intelligence 90 days to come up with a “comprehensive strategy” to hold detainees somewhere other than Guantanamo Bay. The deadline is Tuesday.

But Republican leaders in Congress have shown no signs that they will actually be interested in closing the facility once they see Obama’s plan. Since becoming speaker, Paul Ryan (R-Wis.) has said that Guantanamo Bay should remain open, while just last month, Senate Majority Leader Mitch McConnell (R-Ky.) called Guantanamo “the perfect place for terrorists.”

The front-runners for the Republican presidential nomination also have voiced their support for keeping Guantanamo open – creating little incentive for Republicans in Congress to help Obama close the facility during his remaining months in the White House.

Obama sought to counter that argument on Tuesday.

“Even in an election year, we should be able to have an open, honest, good-faith dialogue about how to best ensure our national security,” he said. “And the fact that I’m no longer running, [Vice President Joe Biden] is no longer running, we’re not on the ballot, it gives us the capacity to not have to worry about the politics. Let us do what is right for America.”

Adam Goldman contributed to this report.