Hern Sees Himself Replacing Mullin as House-Senate Go-Between

House Republican Kevin Hern thinks he’s well-positioned to be Oklahoma’s next senator — and to fill the role of liaison between the two chambers — after he secured President Donald Trump’s endorsement.

Trump tapped Sen. Markwayne Mullin (R-Okla.) to be his next homeland security secretary, setting off an open race to succeed him in November. The path narrowed Friday when Trump put his hand on the scale for Hern and the other Republicans believed to be eyeing the race said they wouldn’t run.

Mullin, a former House member, quickly became known as a senator with relationships across the Capitol, serving ...