From the New York Times moments ago:

The White House has developed a plan to force out Secretary of State Rex W. Tillerson, whose relationship with President Trump has been strained, and replace him with Mike Pompeo, the C.I.A. director, within the next several weeks, senior administration officials said on Thursday.

Mr. Pompeo would be replaced at the C.I.A. by Senator Tom Cotton, a Republican from Arkansas who has been a key ally of the president on national security matters, according to the White House plan. Mr. Cotton has signaled that he would accept the job if offered, said the officials, who insisted on anonymity to discuss sensitive deliberations before decisions are announced.

There are obvious pros and cons to this plan, one being the end of Cotton’s representation of Arkansas in the U.S. Senate.

If my memory is correct, a vacancy in the seat would be filled by gubernatorial appointment until the next statewide general election (November 2018, unless the opening occurs less than four months before the election) when there’d been an election to serve out the remaining time on the term — two years in this case.

UPDATE: A lot of comment on Cotton as a choice, particularly since, among others, his refusal to accept reporting about Russian election meddling and his defense of waterboarding.