It’s not uncommon for Cabinet secretaries to prepare undated letters of resignation during a presidential transition, giving the commander in chief the chance to replace them for a second term. The president decides whether to accept the resignation letters, and the process usually occurs after the election results are clear.

But defense officials say Esper prepared his letter because he is one of the Cabinet officials long expected to be pushed out after the election.

As his tenure may be coming to an end, Esper is helping members of Congress draft legislation that will strip names of Confederate leaders from military bases in a move that could put him further at odds with President Donald Trump.