WASHINGTON — A Democratic senator has a hold on U.S. President Donald Trump's nominee for Air Force secretary, and legislators need to "work through" questions before she can receive a confirmation vote, according to Senate Armed Services Committee Chairman John McCain. 

The delay marks the latest setback for one of Trump's picks for Defense Department leadership. If confirmed, former U.S. Rep. Heather Wilson would be only the second DoD nominee confirmed by the Senate after Defense Secretary Jim Mattis.

The news came as representatives of Mark Green, Trump's second pick to be Army secretary, denied he is withdrawing, amid a backlash over his controversial statements on LGBT issues, Islam and evolution. If Green were to withdraw, he would be the third military service secretary to drop out after being selected by Trump.

On Tuesday, McCain, R-Ariz., said in a brief interview with Defense News that one senator has a hold on Wilson. Lawmakers can levy private holds on a nominee, but the hold must be reported to the senator's party leadership. Holds can be overcome, but require time consuming procedures such as filing cloture — a motion to end debate that requires 60 votes.

"There was one senator who had questions about a facility in her state, and so we are trying to work through that," McCain said. 

In a subsequent interview McCain said the issue, related to an Air Force base in the senator's state, was close to being resolved. "That senator is being reasonable," he said.

Senate Minority Leader Chuck Schumer, D-N.Y., told Defense News on Tuesday that he was not aware of any Democratic senators with a hold on Wilson and that she could come to a Senate vote as soon as this week.

Wilson, a former Republican congresswoman from New Mexico, is currently the president at South Dakota School of Mines and Technology. After leaving the House of Representatives, she spent two years doing contract work for four nuclear facilities, including two New Mexico-based labs, and Lockheed Martin.

The SASC voted to confirm Wilson on April 5, after a several Democrats questioned her over alleged ethical lapses while she was a consultant. Grilled over allegations she had illegally lobbied on Lockheed's behalf and received pay for her consulting work with no record of work, Wilson maintained she had done nothing wrong.

The SASC's top Democrat, Sen. Jack Reed, of Rhode Island, and Sen. Richard Blumenthal, D-Conn., had expressed reservations over Wilson and had planned to review her answers to their questions. However, both said Tuesday they expected her to receive a floor vote soon.

"We're going ahead and trying to get her to the floor," Reed said. "It's the usual around here, that individual members have questions."

Ahead of the news about Green, House Armed Services Committee Chairman Mac Thornberry, R-Texas, repeated his concerns over the administration's slow pace filling top Pentagon jobs, saying that Mattis "cannot do everything single-handedly, and there are several crises in the world he has to manage.

"I continue to be concerned that without Senate-confirmed decision-makers, the Pentagon tends to march in the direction it's been marching in, and that doesn't solve our readiness problems."

McCain said he has "great concerns about the team around Mattis," adding that "the snail's pace [for nominees] we are now at is really very unfortunate." 

Note: This article was updated to include further comments from Sen. McCain.

Joe Gould was the senior Pentagon reporter for Defense News, covering the intersection of national security policy, politics and the defense industry. He had previously served as Congress reporter.

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