Arkansas Sen. Blanche Lincoln (D) now has far more to worry about than just Republican challengers in November. Lt. Gov. Bill Halter announced this morning in a video on his campaign Web site that he is taking on the second-term senator in the Democratic primary.

"Right now, Washington is not working for Arkansas families. But it ought to," Halter says in the video as he steps out of his pickup truck. "If you want your government dedicated to helping middle class families rather than protecting special interests, then join my campaign."

In his announcement, Halter describes his work in Bill Clinton's presidential administration helping balance the federal budget, and helping establish the "scholarship lottery program" as second in command in Arkansas. He says "it's past time to put more Arkansas values in Washington."

The primary takes place May 18.

Several Republicans had already lined up to challenge Lincoln, who either trails or statistically ties each in the polls.