Sen. Markwayne Mullin, R-Okla., right, has blocked the promotion of Army Lt. Gen. Christopher Donahue, left, to the rank of four-star general and as commander of U.S. Army forces in Europe and Africa. (Hermon Whaley Jr./U.S. Army; Senate.gov)

WASHINGTON — Republican Sen. Markwayne Mullin of Oklahoma had included Army Lt. Gen. Christopher Donahue on a list of people he deemed responsible for the Afghanistan withdrawal “disaster.”

“No one has been held accountable,” he wrote on X in September.

Last week, Mullin blocked the promotion of Donahue to four-star general and new commander of U.S. Army forces in Europe, according to a Senate aide who spoke on condition of anonymity. The aide said the block was reportedly at the request of President-elect Donald Trump’s transition team.

Donahue led the 82nd Airborne Division as it worked to secure Kabul’s airport during the chaotic withdrawal from Afghanistan in 2021 and is best known for being the last U.S. service member to leave the country after 20 years of war.

Trump has threatened to fire senior officers and officials who oversaw the evacuation of American troops and Afghan refugees and blames President Joe Biden’s administration for a suicide bomber attack at the airport that killed 13 U.S. service members.

Mullin, 47, has his own grievances with how the withdrawal was carried out. In 2021, as a House member, he twice attempted to embark on unauthorized travel to aid evacuation efforts in Afghanistan but was stopped by the U.S. government.

The Defense Department declined to give Mullin permission to rent a helicopter and fly an American family out of Afghanistan. The State Department then refused to help Mullin enter Tajikistan with large sums of money for a helicopter rental, deeming the plan in violation of Tajikistan’s laws on cash limits.

Mullin later posted a photo of himself on Instagram, saying he was heading home after “helping get Americans out of Afghanistan.”

“President Biden and his administration are absolutely lying to the American people about Americans and our friends being left behind,” he wrote.

Sen. Markwayne Mullin, R-Okla., has had grievances with how the Afghanistan withdrawal was carried out. In 2021, as a House member, he twice attempted to embark on unauthorized travel to aid evacuation efforts in Afghanistan but was stopped by the U.S. government (Sgt. Haden Tolbert/Oklahoma National Guard photo)

Mullin has continued to be an outspoken critic of the withdrawal even though a government watchdog investigation in 2022 found Biden and Trump equally at fault for the rapid collapse of Afghanistan’s security forces.

In 2023, Mullin joined the Senate after a decade of serving in the House and became a member of the Senate Armed Services Committee.

The committee approved nearly 1,000 promotions — including Donahue — early last week before advancing them to the full upper chamber.

Mullin has not publicly disclosed why he stepped in to block Donahue’s promotion from being approved in a traditional voice vote by the full Senate. His office did not respond to a request Monday for comment.

Trump’s transition team also did not respond to a request for comment.

The Senate aide said the team reportedly contacted Republican senators last week with a request to block Donahue’s promotion. There are concerns in the Senate that Donahue will have to call Trump to justify his actions in Afghanistan to have the hold lifted, according to the aide.

Trump’s transition team is reportedly compiling a list of current and former officials who were involved in the withdrawal and is weighing possible courts-martial against them, according to NBC News.

Lawmakers have raised alarms in recent months that Trump would politicize the military in his second term and purge generals who are not sufficiently loyal to him. There is now fear in the Senate that Donahue is “the first in line to face a political loyalty test,” the aide said.

Mullin is a staunch Trump supporter and introduced resolutions in 2022 to remove Trump’s two impeachments from the congressional record. He also voted against the certification of the 2020 elections results.

Mullin came to Congress as a successful businessman who took over his father’s plumbing company when he was 20. He was a star wrestler in high school and briefly worked as a professional mixed-martial-arts fighter.

It is unclear when Mullin could lift his hold on Donahue’s promotion, but the Senate can work around it by holding a time-consuming roll call vote on the floor.

The Senate is scheduled to return from recess next week. Any promotions not approved by the end of the year would need to begin the process anew unless senators agree to waive chamber rules.

Army Lt. Gen. Christopher Donahue led the 82nd Airborne Division as it worked to secure Kabul’s airport during the chaotic withdrawal from Afghanistan in 2021 and is best known for being the last U.S. service member to leave the country after 20 years of war. (Sgt. Alison Strout/U.S. Army photo)

The Pentagon did not respond to a request for comment Monday, but spokesman James Adams in a statement last week praised Donahue’s more than 30 years of military service.

Donahue has served as the commander of XVIII Airborne Corps at Fort Liberty, N.C., since 2022 and would lead the Army’s Europe and Africa headquarters in Wiesbaden, Germany, if approved.

“His appointment comes at an extremely critical time in the European region,” Adams said. “We urge the Senate to confirm all of our highly qualified nominees. Holds on our nominees undermine our military readiness.”