Kansas voters Tuesday will take the first step toward building a new political structure in the state.

Because of retirements and perceived opportunity on the part of candidates, the Republican and Democratic primaries will set the field for the November general election to fill numerous vacancies.

The decision by U.S. Sen. Sam Brownback, R-Kan., to step away from the Senate and run for governor has set off a stampede of candidates — up and down the ballot.

Two veteran U.S. House members, Jerry Moran of Hays and Todd Tiahrt of Goddard, are locked in a contentious battle for the Republican Party nomination for Senate. Also on the GOP ballot are Tom Little of Mound City and Robert Londerholm of Overland Park.

The winner will face the top vote-getter in the Democratic Party primary which features five candidates — Robert Conroy of Shawnee, David Haley of Kansas City, Lisa Johnston of Overland Park, Charles Schollenberger of Prairie Village, and Patrick Weisner of Lawrence.

In the U.S. House

The GOP Senate fight has created a vacuum in Moran’s 1st U.S. House district, and Tiahrt’s 4th U.S. House district.

Six Republicans are vying for the GOP nomination in the 1st and five in the 4th. Only one Democrat has filed to run in the 1st and two Democrats are contending for the nomination in the 4th.

Another retirement, U.S. Rep. Dennis Moore, D-Lenexa, in the 3rd U.S. House district, which includes eastern Douglas County, also sparked a rush of candidates.

Nine Republicans are trying to advance to the general election, and two Democrats. The Republican candidates are Dan Gilyeat of Kansas City, Dave King of Leawood, Garry Klotz of Lenexa, Patricia Lightner of Olathe, Jerry Malone of Leawood, Craig McPherson of Overland Park, John Rysavy of Overland Park, Jean Ann Uvodich of Overland, and Kevin Yoder of Overland Park. The Democrats are Stephene Moore of Lenexa and Thomas Scherer of Prairie Village.

And the 2nd U.S. House District, which includes western Douglas County and represented by freshman Lynn Jenkins, R-Topeka, is being contested. State Sen. Dennis Pyle, R-Hiawatha, is challenging Jenkins on the GOP side, while the Democratic field features Cheryl Hudspeth of Girard, Thomas Koch of Leavenworth, and Sean Tevis of Olathe.

Brownback faces Joan Heffington of Derby in the Republican primary for governor. State Sen. Tom Holland, D-Baldwin City, has no opposition on the Democratic side. The current governor, Mark Parkinson, a Democrat, had been lieutenant governor and stepped into the job when Kathleen Sebelius was appointed to President Barack Obama’s cabinet. Parkinson decided not to seek election.

Secretary of state scramble

Tough battles have emerged in the Republican and Democratic contests for secretary of state. On the Democratic side are Secretary of State Chris Biggs, and Chris Steineger, a state senator from Kansas City. On the Republican side are J.R. Claeys of Salina, Elizabeth “Libby” Ensley of Topeka, and Kris Kobach of Piper.

For attorney general, Ralph J. De Zago of Herington and state Sen. Derek Schmidt of Independence are dueling in the GOP primary to face Attorney General Steve Six, a Democrat, in the general election.

There are no contested primaries for state treasurer. In the Republican Party primary for insurance commissioner, incumbent Sandy Praeger of Lawrence faces David Powell of El Dorado.

The 10th state House district, which covers south Lawrence, Baldwin City, and Wellsville, features a Republican Party primary between Scott James Barnhart of Ottawa and Terri Lois Gregory of Baldwin City. The winner will face state Rep. Tony Brown, D-Baldwin City.