By Kristina Wong - 02/24/16 03:39 PM EST
Defense Secretary Ash Carter admitted he approved the transfer of a Guantánamo Bay detainee without the full support of the chairman of the Joint Chiefs of Staff, Sen. Tom CottonTom CottonCotton not ruling out 2020 White House bid GOP senators avoid Trump questions on rigged election GOP chairman demands number of immigrants granted accidental citizenship MORE (R-Ark.) said, citing a letter from Carter.
"Based on my discussions with Chairman [Martin] Dempsey, I understood that he had some concerns that Shaker Aamer might reengage in terrorist activity after his transfer to the United Kingdom," Carter said in a Feb. 16 letter to Cotton, which the senator released Wednesday.
Carter's letter was in response to a letter from Cotton on Nov. 20 inquiring whether the Defense secretary overruled Dempsey, who was Joint Chiefs chairman at the time.
When the Pentagon announced Aamer's transfer on Oct. 30, a press release had said he was "unanimously approved for transfer by the six departments and agencies comprising" a task force reviewing his case.
One of those six departments is the Joint Chiefs of Staff.
Although Carter said he indeed consulted with Dempsey and other national security leaders prior to the transfer, the Oct. 30 press release stating that the transfer was "unanimously approved" referred to a decision made by the task force in 2009, before Dempsey began serving as chairman.
Dempsey began his term in 2011, taking over for Navy Adm. Michael Mullen. He retired last year.
"This language correctly reflects a decision made by the Task Force in 2009 and was consistent with the press releases issued for previous detainees," Carter wrote.
Cotton blasted that response, calling it "disappointing but unsurprising."
"Aamer is a dangerous man who seeks to harm the United States. That he was transferred with anything less than full agreement of our government and our military is completely unacceptable and speaks volumes about President Obama’s commitment to political talking points over our national security," Cotton said in a statement.
"What else will the Obama administration ‘overrule’ as they seek to close Guantanamo Bay and what impact will it have on our safety and security?” he added.
The revelation comes a day after President Obama sent his plan to close the Guantánamo Bay detention facility to Congress.
Republicans immediately rejected the plan, while Democrats urged their colleagues to give it a fair hearing.
The plan envisions transferring 35 detainees approved for transfer over the next several months, continuing to determine eligibility for release, and bringing the remainder to a secure location in the U.S. with Congress's approval.
Obama's proposal does not list a specific facility or facilities where the detainees could go, instead referencing 13 sites that served as prototypes for the purposes of assessing costs.
Sen. John McCainJohn McCainIs Georgia turning blue? High anxiety for GOP Trump: 'Very disappointed' GOP senator dropped support MORE (Ariz.), one of few Republican supporters of closing Guantánamo, called it a "menu of options" instead of a plan.
Meanwhile, dozens of Republican lawmakers registered their disapproval of the plan, with Sen. Pat RobertsPat RobertsGOP senators avoid Trump questions on rigged election More Senate Republicans pressure Treasury over debt-equity rules GOP leaders advise members to proceed with caution on Trump MORE (R-Kan.) even releasing a short video of himself crumpling up the plan and throwing it in the trash.