Guantanamo Bay is back in the news, and it may become an issue in the presidential race.

A few days ago, former Vice President Joe Biden told a reporter that if he was elected, he would close the terrorist detention facility at Guantanamo Bay, Cuba.

The New York Times said Guantanamo would have been closed during the Obama administration but for generic “political opposition.” But the real reason it didn’t close was a failure of leadership by the previous administration, in which Biden served as vice president.

In 2006, when I was the deputy assistant secretary of defense for detainee affairs, I conducted the first classified study on how to close Guantanamo if ordered to do so. Since coming to The Heritage Foundation in 2007, I have written on this topic and testified before the Obama Detainee Policy Task Force in the spring of 2009 on how to close Guantanamo responsibly.

I also have written extensively not only about President Barack Obama’s relationship with Guantanamo, but also President Donald Trump’s promise—so far unkept—to fill the facility with “bad dudes.”

As for the failings of the Obama administration in this matter, I wrote:

The year 2009 was arguably the most opportune time for the administration to close Guantanamo. The Democrats held a 59–41 majority in the United States Senate when counting Independents who caucused with them. Similarly, in the House of Representatives, the Democrats enjoyed a 257–178 advantage.  If the president needed any legislation to close Guantanamo—a debatable point—or simply the political backing of the majorities in both houses of Congress, the stars were aligned for him to do so.

In his first week in office, on Jan. 22, 2009, Obama signed Executive Order 13492, requiring that the joint detention facility at Guantanamo be closed within a year. The order stated that any individuals still in detention after the one-year mark “shall be returned to their home country, released, transferred to a third country, or transferred to another United States detention facility in a manner consistent with law and the national security and foreign policy interests of the United States.”

Yet, 2009 ultimately proved to be a pivotal year in the detainee saga, not because of any substantial steps toward shuttering Guantanamo, but because, with regard to the question of closure, a series of missteps turned Congress against the administration. These mistakes soured the mood in Congress regarding the administration’s judgment with respect to how to deal with some detainees, and resulted in the Democrat-controlled House and Senate passing legislation to prevent the administration from importing detainees into the United States—a key part of the original executive order and all closure plans.

In May 2009, Obama gave an in-depth speech on national security and Guantanamo detainee policy at the National Archives. He acknowledged that “there are no neat or easy answers” with respect to Guantanamo, but said that he refused “to allow this problem to fester.” In fact, he admitted that “it is my responsibility to solve the problem.” To this end, Obama proposed five distinct categories through which detainees would be disposed:

• Federal court trials.
• Reformed military commissions trials.
• Releasing those ordered released by federal courts.
• Transferring those his administration deemed worthy of transfer.
• Continued military detention of those who cannot be tried but who still posed a national security risk to the United States.

Obama acknowledged that the last category is “the toughest single issue we will face,” and further promised that he was not going to “release individuals who endanger the American people.” He also promised to “work with Congress to develop an appropriate legal regime so that our efforts are consistent with our values and our Constitution.”

The president, however, failed to deliver on these promises, and a month later, on June 9, 2009, the administration transferred Ahmed Ghailani from Guantanamo to the United States for trial in a federal district court in New York. The charges against Ghailani were based on his role in the 1998 U.S. embassy bombings in Kenya and Tanzania. The move was controversial not only because Congress was not given prior notice of the transfer, but also because it was thought that Ghailani was a prime candidate for a reformed military commission trial. Officials in New York were upset because they believed his trial would inspire new terrorist attacks against the city and imposed additional security costs for law enforcement.

Congress reacted swiftly to the Ghailani transfer by adding transfer restrictions to the Supplemental Appropriations Act of 2009, approved on June 24, 2009. The act included language that prohibited the use of funds to transfer any detainee into the United States unless certain criteria were met. If the administration wanted to bring a Guantanamo detainee into the United States for prosecution, the act required that the administration submit a classified plan that included a risk analysis, costs, legal rationale, mitigation plan, and a certification by the attorney general that the transfer posed “little to no security risk to the United States.” Furthermore, no funds could be spent to effect a transfer to the United States until at least 45 days after the plan was submitted to Congress.

Throughout the summer of 2009, Congress held hearings on reforms needed to improve the Military Commissions Act of 2006. On Oct.  28, 2009, Congress passed the [National Defense Authorization Act] for fiscal year 2010. Those meaningful reforms of military commissions became the Military Commissions Act of 2009.

Sixteen days later, on Nov. 13, 2009, then-Attorney General Eric Holder announced that the five Guantanamo terrorists responsible for the 9/11 attacks would be brought to New York to face a criminal trial in federal district court. Politicians from both parties objected vigorously, including Democratic Sen. Chuck Schumer and Republican Rep. Peter King, both from New York.

As if those moves did not poison the relationship between the Obama administration and Congress enough with respect to Guantanamo, on Dec. 15, 2009, Obama issued a presidential memorandum to the attorney general and secretary of defense to purchase the state-run Thomson Correctional Facility in Thomson, Illinois, for the express purpose of housing Guantanamo detainees. The controversial move produced another political backlash against the administration. Even Obama’s diehard supporter from Illinois, Democratic Sen. Dick Durbin, who at first supported the move, withdrew his support when it became “politically impossible.”

As a result of these moves, Congress began to include a provision in annual appropriations or defense authorization enactments that barred the use of funds to construct or modify a facility in the United States to house detainees who remain under the custody or control of the Department of Defense.

The closure of the Guantanamo Bay detention center did not have to unfold in such a contentious fashion. The Obama administration could have worked with Congress to close Guantanamo in a responsible manner. Although closing the facility within the self-imposed one-year deadline was ambitious, it could have been accomplished by sharing the work and the credit with Congress. By provoking Congress and unilaterally pursuing ill-conceived policies, the administration was no longer just making big promises it could not fulfill; it began to make big mistakes that haunt it to this day.

I include this historical background as context. Any sensible policy for closing Guantanamo responsibly without increasing dangers to the American people should take these considerations into account.