Sen. Blanche Lincoln (D-Ark.) is reasserting credit for her tough derivatives amendment, which passed the Senate as part of the financial reform package last week.

Labor unions said it was their support of Lt. Gov. Bill Halter's (D) primary challenge that spurred Lincoln to shepherd the provision through the legislative process. But a new TV ad from Lincoln's campaign highlights her leadership on "Wall Street reform."

She faces Halter in a June 8 runoff.