Democratic House candidates across the country are signaling a desire to make the GOP’s plan for Medicare reform a real issue — early and often — in the 2012 election.

From California to New Hampshire, Democrats are launching their campaigns with a united message on Medicare and hoping it will pay off next year.

That message? “Your Republican member of Congress voted to end Medicare as we know it, and it’s time for someone new.”

In Colorado, state Sen. Brandon Shaffer (D) launched his campaign against freshman Rep. Cory Gardner (R) this week by laying into Gardner for his vote in favor of the House Budget Committee Chairman Paul Ryan’s (R-Wis.) budget that would turn Medicare into a voucher program.

Shaffer made the attack the keynote of his announcement, saying Gardner “just gutted Medicare with his vote on the Ryan budget.”

Other Democratic candidates who have made the Medicare plan a key part of their rollouts include activist Ann McLane Kuster, a repeat challenger to Rep. Charlie Bass (R-N.H.); Colorado state Rep. Sal Pace, who faces Rep. Scott Tipton (R); Dr. Ami Bera, who is running against Rep. Dan Lungren (R-Calif.) for the second straight cycle; Illinois state Sen. Dave Koehler, who is challenging Rep. Bobby Schilling (R); and Wisconsin state Sen. Pat Kreitlow, who is running against Rep. Sean Duffy (R).

Kuster railed against Bass’s vote in an op-ed, Bera held a town hall devoted to the GOP’s Medicare plan, and the rest all mentioned Medicare as a motivating factor for their campaigns.

The man who got the ball rolling, of course, was businessman Rob Zerban, who took the fight directly to the man responsible for the Medicare proposal, Ryan. Zerban’s challenge to Ryan instantly became a cause celebre for national Democrats earlier this year when it began to look like the GOP’s Medicare proposal would be a real liability.

Ryan, despite coming from a swing district, is a second- or third-tier target for Democrats. The others, though, are all among the most targeted Republicans on the map.

Medicare continues to poll well as an issue for Democrats – a recent Bloomberg poll showed that 57 percent think they would be worse off under Ryan’s plan, while just 34 percent think they would be better off – so it’s no surprise that they keep going back to the well.

Democrats have won a special election in upstate New York where the Medicare proposal was cited as the main reason for the upset, and Democratic Congressional Campaign Committee Chairman Steve Israel (N.Y.) stated publicly that the GOP’s Medicare proposal gave him new hope for winning back the House in 2012.

The question for Democrats is whether the issue is as relevant in November 2012 as it is in July 2011.

People tend to be pretty passionate about entitlement programs, and Democrats are banking on them continuing to be strongly against the GOP plan next year.

At the same time, when Rep. Anthony Weiner’s (D-N.Y.) scandal broke, much of the Democrats’ messaging momentum on Medicare was thwarted. And, with President Obama floating the possibility of cuts to Medicare in a grand bargain on the debt ceiling there is some concern in Democratic strategist circles that the party will lose its political high ground on the issue.

Republicans, for their part, have struggled to justify the vote, and are hoping the issue doesn’t ruin their 2012 election prospects in the same way the Democratic health care bill swamped that party’s 2010 efforts.

There is anecdotal evidence that people don’t quite know what to think about Medicare. Results of a focus group of independents released today by Resurgent Republic, a conglomerate of GOP consultants and pollsters, shows that they are strikingly unfamiliar with the the Republican budget plan.

Of course, what they do know about the plan makes them not like it, and explaining the finer points is difficult to do. Democrats have a much simpler message to sell, and they are — quite literally — running with it. Look for them to keep running with it until they have a good reason not to or it stops paying dividends.