Defense Secretary Jim Mattis is reportedly “not happy” the White House is arguing with him over who should take the top job in the Pentagon’s policy shop, Foreign Policy reports.

According to FP, Mattis wants former George W. Bush era Pentagon official Mary Beth Long to come aboard as Under Secretary of Defense for Policy, but the White House is insisting he go with Mira Ricardel, a Trump transition team member who also served in the Bush administration.

This doesn’t seem to be a fight over qualifications, however.

Instead, FP reports that one of the issues the Trump administration has is that during the campaign, Long was among more than 100 Republican national security leaders who signed an open letter referring to then-candidate Trump as “fundamentally dishonest” and unfit for office, among other complaints.

Long later walked back the letter’s criticism and dropped her “Never Trump” position, telling NPR in November that it was “a moral and civic duty to get behind this president.”

Still, the report from FP suggests an apparent “blacklist” is in effect for Republicans who openly opposed Trump prior to the election.

Read the whole story from Business Insider.

Featured image courtesy of AP.