Wichita ? Two conservative Kansas congressmen who were swept into office four years ago during a tea party surge faced unusually acrimonious primary races Tuesday from Republican challengers trying to tap into voter dissatisfaction with Washington.

The state’s hottest congressional race was in the aircraft manufacturing hub in south-central Kansas’ 4th District, where Republican U.S. Rep. Mike Pompeo of Wichita was attempting to fend off a challenge from popular former Congressman Todd Tiahrt. Tiahrt held the seat for 16 years before giving it up in 2010 for an unsuccessful GOP primary run against U.S. Sen. Jerry Moran.

In the 1st District primary, Clyde farmer and educator Alan LaPolice was challenging U.S. Rep. Tim Huelskamp, trying to capitalize on discontent with the congressman’s stances on agricultural issues and recent spats with party leaders.

Both Huelskamp and Pompeo were first elected in 2010, when the tea party movement helped Republicans claim control of the House. But some of their former supporters now argue the incumbents haven’t done enough to end dysfunction in Congress.

Tiahrt has said he was running because he can no longer sit by and “see all the hard work I did deteriorate.”

With the Wichita economy ailing from its depressed aviation industry, Tiahrt’s campaign has focused on whether Pompeo has done enough to help his district. Tiahrt points to federal money he brought home while in Congress to public works projects and aviation companies, while Pompeo criticizes federal largesse and suggests local businesses are better served by lower taxes.

Ray Laboeuf, a 62-year-old aircraft worker retired from the Air Force and Boeing, said he got excited when he found out Tiahrt was running for his old seat. Tiahrt’s opposition to the National Security Agency monitoring of domestic emails and phone calls resonated with him.

“They don’t need to be monitoring every email and phone call,” Laboeuf said Tuesday as he left his Belle Plaine polling place in south-central Kansas’ Sumner County. “That is a Fourth Amendment issue — don’t shred the Constitution.”

Darrel Croxson, 50, a machinist at Spirit AeroSystems in Wichita, voted for Pompeo in the 4th District race.

“I definitely agree we need to cut government spending. Less government is better,” Croxson said in Belle Plaine.

The 4th District Republican primary fight is playing out in the home district of Charles and David Koch, who have built a network of conservative organizations nationwide. The Koch money is backing Pompeo. The winner will face Democrat Perry Schuckman.

In the 1st District of western and central Kansas, Huelskamp was caught in an unexpectedly tough race with a political novice as he seeks a third two-year term.

Huelskamp, a tea party favorite and Fowler farmer known for his criticism of the GOP leadership in Washington, was battling LaPolice in a race that has shaped up to be a referendum on whether Huelskamp has put his own ideology above his constituents’ interests.

Huelskamp has angered Kansas farmers by repeatedly voting against the Farm Bill. He also is co-sponsoring legislation that would phase out a renewable fuel program that bolsters the U.S. market for ethanol. His district includes 11 biofuel plants and vast fields of corn and sorghum.

After running unopposed two years ago, Huelskamp not only faces a primary challenge but two Democrats are seeking their party’s nomination to run against him — former Manhattan Mayor Jim Sherow, a history professor at Kansas State University, and Bryan Whitney, a political science student at Wichita State University.

The other two Republican incumbents face little opposition. U.S. Rep. Kevin Yoder of Overland Park is unopposed in the primary and U.S. Rep. Lynn Jenkins is fending off a long-shot challenge.