Republican Rep. Roger Marshall of Kansas has launched a bid for U.S. Senate. The incumbent, GOP Rep. Pat Roberts is retiring. Marshall, in his third term, joins a field that includes the former Kansas Secretary of State Kris Kobach. It may also eventually include Secretary of State Mike Pompeo, who has deflected questions about whether he will run.

The decision adds Marshall to the list of 2020 House Retirements, which now number 19.  The Kansas 1st District is larger, by area, than the state's other three districts combined.  It is also the most conservative. Despite the lack of an incumbent running in 2020, it is expected to remain in GOP hands.