With Thursday marking the two-year anniversary of the signing of President Obama's economic stimulus package, Republicans are using the opportunity to hit vulnerable Senate Democrats in the continuing battle over its impact. 

The National Republican Senatorial Committee is out with a new Web video slamming five Senate Democrats who backed the package by highlighting their words of support.

The 60-second video includes clips of Senate Democrats up for reelection in 2012, including Sens. Claire McCaskill (Mo.), Sherrod Brown (Ohio), Joe Manchin (W.Va.), Bill Nelson (Fla.) and Jon Tester (Mont.). 

The video employs a clip of McCaskill calling the stimulus "wildly successful" in an interview with Fox News, while a split-screen graphic highlights Missouri's 9.5 percent unemployment rate. 

Along with the video, the committee targets each of the five Senate Dems in news releases, highlighting their support for the stimulus and challenging them on the president's newly released budget. 

Some House Republicans, meanwhile, are working to defund what's left of the stimulus. Freshman Rep. Sean Duffy (R-Wis.) is championing a bill that would return some $168 billion in unused stimulus funds to the U.S. Treasury. 

To mark the one-year anniversary of the $787 billion package, Democrats engaged in a full-court press on its benefits and hit Republican opponents of the bill as "hypocrites." Last year, the Democratic National Committee released a Web video of its own, charging, "Republicans don't want to acknowledge that the recovery act has created jobs." 

No similar coordinated efforts this time around from Democrats, but on Capitol Hill lawmakers are pressing Republicans over the party's proposed spending cuts, arguing they stand to derail the nation's economic recovery.