Early in her tenure as homeland security secretary, Kristi Noem made some calls that rankled Coast Guard officials, including shifting resources away from a search and rescue mission to find a missing service member and putting them toward efforts to deport migrants, sources told NBC News.

The dynamic has only worsened in recent months, and in one contentious incident, Noem's top adviser Corey Lewandowski berated Coast Guard flight staff and threatened to fire them for taking off without one of the secretary's personal items on board: a heated blanket.