Sen. Blanche Lincoln (D-Ark.) said her Republican opponent was "tie[ing] one arm behind the backs of Arkansans" because he didn't direct any federal money to his district through the recently passed transportation bill.

Lincoln noted that Arkansas's 1st, 2nd and 4th districts — all held by Democrats — will get federal money through the bill, but not the 3rd district, which Rep. John Boozman (R-Ark.) represents.

"I will not tie one arm behind the backs of Arkansans," Lincoln said in a statement. "Arkansas taxpayers deserve to get a good return on their investment and I consider it part of my responsibility to ensure these important projects are justified and are funded."

Lincoln, who chairs the Senate Agriculture Committee, has repeatedly pitched voters on her ability to deliver federal resources to her small state. It's a tried and tested argument, but it's riskier to make in an environment where there are street protests about government spending.

Boozman joined the House Republicans' "earmark moratorium" in March. Partly as a result, the amount of earmarked money is down by roughly 40 percent in three 2011 appropriations bills in the House compared to last year’s bills, according to an analysis by the nonpartisan Taxpayers for Common Sense.

Boozman "has had an election-year conversion to abstain from earmark requests," according to Lincoln's camp.

A spokesman for Boozman said the country "can't run" on a "Visa card."

"At a time when our nation is borrowing 41 cents for every dollar they spend, Arkansans are demanding that Congress exercise some fiscal restraint," Patrick Creamer, a spokesman for Boozman, said in a statement. "You can't run a country on a Visa card, Senator Lincoln." 

—Walter Alarkon contributed to this post.