The winner will face incumbent Democrat Nancy Boyda, who bounced Ryun two years ago after he served five terms in Washington.

With 46 percent of the precincts reporting, Jenkins was leading 52 percent to 48 percent. The district covers all or parts of 26 counties in eastern Kansas.

Elsewhere, State Sen. Nick Jordan defeated Paul Showen, a retired construction worker and real estate agent, in the Republican primary in the 3rd District. Jordan was up 76 percent to 24 percent, with 78 percent of the precincts reporting.

Both are from Shawnee, and Jordan now will face Democratic incumbent Dennis Moore in the fall. The district encompasses the Kansas portion of the Kansas City metro area.

Ryun and Jenkins continued to campaign throughout the day, making calls to voters and visiting with them during the lunch hour. Turnout was expected to be sparse in the 2nd District, but those who did venture in the summer heat cited high energy prices and low performance from the economy as key issues.

Democrats said they were supporting Boyda, and if they had to choose between Jenkins and Ryun, would support Jenkins.

Josh Simms, a Topeka therapist, called Ryun "just an old-school Washington politician."

"I just don't buy the argument from him that he's a fiscal conservative," Simms said.

But Rodney Callahan, a Republican and a Topeka Wal-Mart employee, said he felt Ryun deserved another crack at Congress.

"He's got pretty good values," Callahan said.

In the 1st District of western Kansas, neither Republican Rep. Jerry Moran, of Hays, nor Democratic challenger James Bordonaro, of Emporia, have primary opposition.

That's also the case in the 4th District of south-central Kansas, where Republican Rep. Todd Tiahrt, of Goddard, is seeking re-election. His Democratic challenger is state Sen. Donald Betts, of Wichita.