Deep State plant and traitor
Assuming for the sake of argument that is true, it's a toothless threat. somebody is going to occupy that position, whether the are called "acting" or "interim" makes no functional difference. The Senate is sitting on its hands confirming US Attorneys, but only on a technicality are those positions unfilled - Sessions has appointed people to fill all of those slots on interim basis.
From day 1, it was the damned Dems who were threatening to go "postal" on Trump, screaming about how that would be "NIXONIAN" and a reason to impeach him. And THAT is laughable, since they are not only in the minority, but because it isn't a high crime, nor even a misdemeanor.