TOPEKA, Kan. — Activists in both parties strongly suspect that political skullduggery led to two Kansas candidates with the same first and last name running against each other in a congressional primary, but a state board on Monday faced its own challenge: How should ballots differentiate between the two Wichita men?

Republican voters in the 4th District in the Wichita area are now set to choose Aug. 7 between Rep. Ron Estes , the incumbent, and Ron M. Estes , the challenger. The Kansas secretary of state's office devised the listing after Ron M. Estes filed to challenge the freshman congressman in the GOP primary. A Democratic candidate objected, arguing that the plan to list the incumbent with "Rep." gave him an unfair advantage.

But the all-GOP, three-member State Objections Board led by Secretary of State Kris Kobach concluded Monday that using middle initials to distinguish the candidates on the primary ballot still might prove too confusing for voters.

Democratic candidate Laura Lombard, who filed the objection, surmised that confusing voters was the point for the challenger or others backing him. So did Rep. Ron Estes' chief of staff, Josh Bell.

"I definitely do think someone put him up to it," Lombard told reporters after the board's decision, saying the Estes vs. Estes race has become a "circus."

Rep. Ron Estes, a former two-term state treasurer, won a tougher-than-expected election last year for the seat formerly held by U.S. Secretary of State Mike Pompeo. Meanwhile, Ron M. Estes said in an email that he's worked for aircraft manufacturer Boeing for 40 years.

Both men are 61.

The challenger did not attend the Objections Board meeting in Topeka or send a representative, though he called the board "corrupt" in an email afterward and derided the decision as favoring "career politicians."

No filings were available for the challenger on the Federal Election Commission's website Monday, suggesting he might not raise or spend $5,000 for his campaign. The incumbent spent almost $422,000 on his special election campaign.

The challenger has communicated with The Associated Press only through emails and hasn't made any public appearances so far. He filed to run May 31, the day before the deadline.

"We're less than two months before the primary," said Bob Beatty, a Washburn University of Topeka political scientist. "Most serious candidates in primaries have been campaigning for over a year."

The challenger and his wife, a retired teacher, are registered Republicans who've consistently voted in GOP primaries starting in 2010. But online campaign finance records show that together, the challenger and his wife have a history of contributions to Democratic candidates.

His wife contributed a total of $1,155 to James Thompson, the Democratic nominee in last year's special election against Rep. Ron Estes. Thompson is running again. The challenger said in an email that he backed Thompson as well because Thompson "stood up to" the congressman.

As for the issues before the board, Lombard worried that the "Rep." designation for the incumbent would carry over to the November ballot should he win the primary. Kobach said it wouldn't because it would no longer be necessary to avoid voter confusion.

A Kansas election law generally prohibits listing a candidate's name with a title. But the statute makes an exception for using "a prefix or suffix when necessary to distinguish one candidate from another."

"I think that's the best we can hope for with this impostor candidate filing to run," said Bell, the incumbent's chief of staff.