Four U.S. Republican senators sent a letter to President Donald Trump this week urging him to transfer more than 700 “battled-hardened” Islamic State (ISIS/ISIL) jihadis captured by the American-allied Syrian Democratic Forces (SDF) to the American military prison in Guantánamo Bay, Cuba (Gitmo).

Soon after taking office, the Trump administration expressed an interest in sending newly captured “bad dudes” linked to the Taliban, al-Qaeda, ISIS, and other Islamic jihadi groups to the facility, as the president promised.

In March 2017, news reports revealed that the Trump Department of Defense (DOD) was planning to spend up to $500 million on upgrading the Guantánamo facility.

Although President Barack Obama attempted to close the prison by executive fiat, Trump signed his own executive order in early 2018 to keep the prison open indefinitely.

Now, Sens. Tom Cotton (R-Arkansas), John Cornyn (R-Texas), Ted Cruz (R-Texas), and Marco Rubio (R-Florida) are calling on the president to make good on his promise to fill Gitmo with some “bad dudes.”

The senators wrote:

Our partners, the Syrian Democratic Forces (SDF), are currently detaining over 700 of these battle-hardened terrorists in northeast Syria. … Given the rapidly shifting dynamics in Syria, it is possible that these terrorists may escape or be released from SDF custody in the coming weeks and months. It is imperative that these Islamic State fighters not be released. … We urge you to consider transferring the worst of these Islamic State fighters to the detention facility in Guantanamo Bay, where they will face justice.

The senators warned that if released, the ISIS jihadis “will take up arms” against America’s allies in Syria and Iraq “or attempt to infiltrate the United States and Europe to carry out terror attacks against civilian targets like they have already done in France and Belgium.”

The Trump administration has only transferred one detainee out of Gitmo who was approved for release under former President Barack Obama, bringing the prison population that reportedly requires millions of dollars to manage per inmate down to 40.

U.S. authorities have deemed about half of the detainees (26) as “forever prisoners” or too dangerous to release.

In his failed quest to shut down the facility, the Obama Administration released more than 200 terrorists, less than half of the 532 liberated under George W. Bush.

“The U.S. hasn’t transferred any new detainees to the detention facility — which currently houses 40 detainees — in more than ten years. Doing so would require the U.S. to prove that the detainee in question is affiliated with a force that the U.S. is in armed conflict with,” the Washington Examiner pointed out on Tuesday, adding:

Both administrations have argued that ISIS is covered by the 2001 Authorization for Use of Military Force Against Terrorists, which permits the president to use military force against those responsible for the 9/11 attacks.

But experts have noted that such an interpretation of the law has not been challenged in court. As a result, an ISIS prisoner moved to Guantanamo would “likely” file a “habeas petition in federal court to challenge the scope of the government’s detention authority,” according to Charles Stimson and Hugh Danilack, who co-authored a Heritage Foundation report on the matter.

President Trump has vowed to withdraw the nearly 2,000 American troops in Syria, prompting the Kurdish People’s Protection Units (YPG)-led SDF to accuse the United States of abandoning them amid threats of an attack by Turkey.

Ankara considers the YPG, which leads and makes up the majority of the U.S.-backed SDF, to be linked to the Kurdistan Worker’s Party (PKK) communist terrorist group that is waging a deadly insurgency inside Turkey. U.S. support for the Syrian Kurdish groups has strained the relationship between NATO allies the United States and Turkey.

America’s withdrawal from Turkey has also sparked concerns that it may lead to an ISIS resurgence.

The Pentagon’s inspector general (IG) reported in November 2018 that ISIS remains a threat in both Iraq and Syria although the group only controls one percent of the territory it once held.

ISIS has morphed into “an effective clandestine” group that “moved underground and is acting as an insurgency in both countries,” the watchdog agency added.

U.S. National Security Adviser John Bolton recently conditioned the American withdrawal on ensuring ISIS’s lasting defeat and assurances by Turkey that the Kurds will be safe, adding that a residual force would remain in southern Syria to combat the Iranian threat.