U.S. Sen. Pat Roberts, R-Kan., (left) and Dr. Milton Wolf shake hands earlier this year at a Douglas County GOP event. Roberts has decided he will not debate Wolf before the Aug. 5 Republican Party primary.

U.S. Sen. Pat Roberts will not debate his main challenger, Milton Wolf, before the Aug. 5 Republican Party Primary.

Roberts’ executive campaign manager Leroy Towns said Friday the tea party-backed Wolf has failed to articulate positions on issues “beyond his vague rhetoric and false attacks on Sen. Roberts.” Towns said Wolf “is widely regarded as an embarrassment to Kansas and to Republicans.”

Wolf’s campaign spokesman Ben Hartman said it was “unbecoming” of Roberts to refuse to debate.

“This is a very important time in our country and it is very important to have questions and discussions,” Hartman said. Plus, he noted, that Roberts had promised earlier that he would debate Wolf.

But Towns said Republicans have had many chances to compare the candidates because he said Roberts and Wolf have shared the stage at numerous GOP events.

Hartman said there have been a handful of events where the two candidates have crossed paths, but seldom have they spoken on the same stage.

At a Douglas County GOP event on Jan. 20 at Famous Dave’s restaurant, Roberts and Wolf were both invited to speak. The candidates briefly greeted each other before the meeting, then Roberts spoke first.

After Roberts’ talk, candidates for state insurance commissioner participated in an hour-plus forum. Wolf then addressed the meeting before the group adjourned. Roberts had already left the meeting before Wolf spoke.

At that meeting, both Roberts and Wolf blasted President Barack Obama and the Affordable Care Act, but Wolf also blamed Roberts for the ACA because Roberts voted to confirm former Kansas governor Kathleen Sebelius as secretary of Health and Human Services, which headed formation and implementation of the ACA.

Bob Beatty, a political science professor at Washburn University, said Roberts’ refusal to debate Wolf could hurt Roberts in the primary. But Beatty said the Roberts’ campaign could be thinking it would hurt Roberts more if Roberts committed a gaffe during the debate.

“It’s very common in primaries, in both parties, for incumbents not to want to debate if they feel like they have a lead in the race. They’re incumbents and they’re already well known and they feel they have little to gain,” Beatty said.

Two lesser-known candidates, D.J. Smith of Osawatomie and Alvin Zahnter of Russell, are also on the Republican ballot. On the Democratic side, Shawnee County District Attorney Chad Taylor faces Lawrence attorney Patrick Wiesner.