In what could be the start of a wave of post-election firings, President Trump announced in a tweet Monday that Defense Secretary Mark Esper "has been terminated." The president said National Counterterrorism Director Christopher Miller will become acting defense secretary effective immediately. The Hill notes that Trump and Esper have had a "rocky relationship" since early June, when Esper, who was confirmed by the Senate in July 2019, held a press conference at the Pentagon to announce that he opposed using the Insurrection Act to deploy troops to racial justice protests. Sources told NBC last week that Esper, expecting to be pushed out after the election, had already prepared a resignation letter. (More Mark Esper stories.)