Veteran Sen. Richard G. Lugar, Indiana Republican, is trailing his primary challenger by 5 percentage points in a new poll released Thursday.
State treasurer Richard Mourdock has 44 percent support compared with 39 percent for Mr. Lugar, according to a poll funded by the Mourdock-supporting group Citizens United.
The margin is the largest yet for Mr. Mourdock, who is hoping voters’ anti-incumbent mood and the deep pockets of conservative groups will allow him to unseat the six-term senator.
The poll also showed Mr. Lugar’s favorability among Republican voters dropping to 44 percent. Mr. Lugar led Mr. Mourdock until last week, when a McLaughlin poll showed Mr. Mourdock up by 1 percentage point.
The fiscally conservative Club for Growth, which has spent hundreds of thousands of dollars to attack Mr. Lugar as a liberal Washington insider, released a new television ad this week that begins with a narrator asking, “What happened to Dick Lugar?”
“He was a respected national leader, a statesman,” the ad says. “Then he became part of the problem, joining the liberals in voting for record debt, bailouts and tax hikes. Now he’s clinging to power, throwing mud at conservative Richard Mourdock with ads that have been called ‘misleading,’ ‘weak’ and ‘desperate.’”