U.S. Rep. Roger Marshall will rely on the Kansas State Fair as backdrop Saturday to articulate the next phase of his political career.

Marshall, who has been considering for months a race for U.S. Senate due to pending retirement of four-term Republican Pat Roberts, promised a "major announcement" regarding his future at 10 a.m. at the House of Capper on the fairground in Hutchinson.

The tone of a senior adviser to Marshall quoted in a news release Tuesday suggested the three-year veteran of Congress was in campaign mode. It just remains to be seen whether that future includes a race for the Senate or a bid for re-election in the House serving the rural 1st District stretching from the Colorado border to Emporia.

"Families, farmers, workers, patients, the unborn and all hard-working Americans have had no greater champion in Congress, and it is more vital now than ever that those Kansas values continue to have a tireless advocate," said Eric Pahls, the Marshall aide.

Marshall, a physician from Great Bend, expects to complete this week an eight-month tour of the state's 105 counties. He also would be allowed to transfer $1.4 million from his House campaign account to a Senate fund.

His announcement would follow the speech Friday by U.S. Secretary of State Mike Pompeo at a Landon Lecture on the campus of Kansas State University. Pompeo, a former Kansas congressman, has been mentioned as a potential Senate candidate, and has cast a significant shadow over debate about who might follow in Roberts' footsteps.

Despite statements by Pompeo that a campaign for Senate was "off the table" in 2020, Republicans in Kansas and Washington, D.C., appear eager for President Donald Trump's top diplomat to step into the contest.

GOP candidates who have declared include Kansas Senate President Susan Wagle, former Kansas Secretary of State Kris Kobach and former Kansas City Chiefs player Dave Lindstrom.

Kansas Treasurer Jake LaTurner also had declared for Roberts' Senate seat, but on Wednesday he decided to leave the crowded field and challenge first-term incumbent U.S. Rep. Steve Watkins in the 2nd District — just as former Kansas Gov. Jeff Colyer urged LaTurner to do last week.

Candidates for the Democratic Party's nomination for Senate include former U.S. Rep. Nancy Boyda, former U.S. prosecutor Barry Grissom and Manhattan City Commission member Usha Reddi. No Kansas Democrat has won a statewide election for U.S. Senate since 1932.