Chairman of the House Finance Committee Paul Ryan (R-Wis.) has put himself in the spotlight with his budget plan. (Melina Mara/THE WASHINGTON POST)

51 percent for President Obama in 2008. So some Democrats are asking whether they can take a symbolic scalp next year by defeating the architect of the Republicans’ budget plan.

The argument: Ryan flew under the radar for years, even occasionally breaking with his party to bolster his standing in his blue collar, Rust Belt district. For example, he voted for the 2009 auto bailout — his district has two auto plants.

"A lot of guys get to vote how they want, then go home and go fishing,” he told the Milwaukee Journal Sentinel in 2009. “I've got to vote and then go home and explain what I did and why I did it." But he’s more conservative than his constituents. Now that he’s released a budget that would drastically overhaul Medicare, Democrats think they can make that clear.

It won’t be easy, and redistricting will likely make it harder. Republicans control map making here, and they can use it to make Ryan’s seat less marginal by adding parts of deep red Waukesha County from Rep. James Sensenbrenner 's (R) suburban Milwaukee district. The one caveat: as the senior Republican House member in the state, Sensenbrenner has a lot of clout and might balk at the idea. Shoring up Ryan with voters from any other district would imperil vulnerable Republicans. There’s another complication to consider — if Democrats take back the state senate in recall elections this summer, they will have to sign off on the new map.

Yet even with the current lines, Ryan has always won by huge margins. He comes from Jainesville, the most Democratic part of the district. Even if these voters are starting to sound skeptical, they’ve gone with Ryan for over a decade now even as he frequently talks back home about Medicare reform. CBS News found voters “mostly supportive.” And Ryan has no trouble raising money; he has more than $3.2 million in his war chest.

“Despite the Democrats' best attempts, Paul Ryan's willingness to take on Washington's spending addiction has never been a political liability for him in a competitive district,” said National Republican Congressional Committee spokeswoman Andrea Bozek.

Democrats point out that Ryan’s challenger in four of the last six elections was a retired orthopedic surgeon who didn’t believe in fundraising. Last year, it was an unemployed party activist. The district is on the Democratic Congressional Campaign Committee list of 61 GOP-held seats to target. Although it hasn’t been part of all of their ad buys, they have run some radio spots.

Ryan already has a Democratic challenger — local businessman Rob Zerban, who got in the race about a week ago. Some liberal activists are promoting Chris Larson, a state senator who rose to prominence during the state’s budget fight as another potential candidate. But Larson’s district and Ryan’s only partially overlap.

“Unlike other years, he’s gotten a start very early with the campaign infrastructure,” said Graeme Zielinski, spokesman for the state Democratic party. In past cycles, he said, “we haven’t done a good job educating people in the district about Paul Ryan.” While the party is not getting involved in town hall disruptions, they are filming them, and some local activist groups are working on stirring up dissent.

Democrats also have a model for success — former Rep. John Spratt (D-S.C.). Like Ryan, he usually won by large margins in an increasingly conservative district. He was the chairman of the budget committee. And he lost his seat in 2010. Of course, that was the best Republican year in decades. Without that kind of wave, Democrats might force Ryan to actually defend his seat, but they have only a slim chance of taking it away.