Evan McMorris-Santoro May 12, 2010, 2:44 PM

Arkansas Republican Party chairman Doyle Webb says he’s pretty sure the hotly-contested Democratic Senate primary won’t come to an end on May 18. At a meeting of state GOP chairs in Maryland yesterday, Webb told me that thanks to the little-discussed campaign of D.C. Morrison — who’s running from the right against both Sen. Blanche Lincoln and Lt. Gov. Bill Halter — the Senate primary is likely headed for a run-off. That’s a positive development for Republicans hoping to flip the seat, Webb said.

“It’s great news,” he said. Webb said a run-off, which would be held on June 8, would eat up valuable resources and keep the Democrats focused on each other rather than the Republicans.

As for his party’s own primary, Webb predicted Rep. John Boozman will win the eight-way race for the GOP Senate nomination, but he said the victory is not yet assured. Either way, he said, he feels confident that Democratic infighting will give his party the edge in the fall.

Morrison — who has the support of Libertarians and kicked off his campaign with public doubts about global warming — has been a factor in some recent polling. A Mason-Dixon poll released last week showed Morrison with 7% of the vote. Lincoln led with 44% and Halter came in second with 32%.

If those numbers hold, there would be three more weeks of campaigning between Halter and Lincoln after May 18. A candidate has to reach at least 50% to avoid a run-off in Arkansas. (Mike Madden reported today that internal Lincoln polls show her crossing the 50% mark on the May 18.)

Webb said that even if there’s no run-off, Morrison has made sure that conservative issues have been raised in it midst of the Democratic primary, which has served to “let voters know what their in for” with either Democrat.

“I feel very good about this race,” Webb told me.

AR-SEN, Bill Halter, Blanche Lincoln, D.C. Morrison