If its House majority is in jeopardy, the GOP’s own success is partly to blame. The Republican rout gave the party control of 242 Congressional districts, its most since 1949. Sixty-one of those districts were carried by President Obama in 2008; 14 were captured by John Kerry four years before that. Maintaining a historical high-water mark in 2012 was never going to be easy. Midterm-election voters tend to be older and whiter, a cohort that tilts toward the GOP. Republicans are unlikely to have a similar cushion next year, when Obama’s presence on the ballot will likely boost down-ballot Democrats.

“Republicans voting to end Medicare is a defining issue of this Congress and the American people are already rejecting it at town hall meetings across the country,” says Jesse Ferguson, spokesman for the Democratic Congressional Campaign Committee. “As House Republicans choose taxpayer giveaways for Big Oil and tax breaks for the ultra rich instead of Medicare for seniors, then seniors and middle class families are going to choose Democrats in the next election.” The DCCC recently launched an ad campaign, which ranges from radio spots to robo-calls, against 50 Republicans it considers vulnerable, decrying their vote for the Ryan budget. Though relatively few dollars have been directed to the effort yet, the “Drive to 25″ marks the start of a sustained push to pillory Republicans for kowtowing to corporate interests instead of safeguarding seniors from rising health-care costs.