While many conservative pundits are giddy about Romney’s choice of Paul Ryan as his vice presidential candidate, the poll numbers suggest that this could really hurt his chances of winning the election, especially in some of the key swing states.

But in polls, most of those older and blue-collar voters have consistently recoiled from the centerpiece proposal of Ryan’s budget: his initiative to convert Medicare from its existing structure, in which Washington pays doctors and hospitals directly for care they provide to seniors, into a premium support or voucher system that would provide seniors a fixed sum of money to either purchase private insurance or buy into the existing program…

The electoral impact of Ryan’s plan is so crucial because less affluent whites have become so central to the GOP’s electoral prospects. Republicans have carried a majority of white seniors in each presidential election since 2000, with their share of the vote among them rising from 52 percent that year to 55 percent in 2004 to 58 percent in 2008; they soared to 63 percent with those voters in the 2010 House elections, according to exit polls. Over the past three presidential elections, Republicans have also amassed commanding margins among blue-collar whites, attracting around three-fifths of them each time; those voters also gave GOP House candidates 63 percent of their votes in 2010. Polls this year have found President Obama struggling with both older and blue-collar whites — though recent Quinnipiac University/CBS News/New York Times surveys have shown the president regaining some ground in battleground states with non-college white women, the so-called “waitress moms.”…

But among both blue-collar and older whites attitudes about Medicare are very different. In March, the United Technologies/National Journal Congressional Connection Poll offered respondents two options for the program. Just 19 percent of whites older than 65 endorsed Ryan’s approach, which said “Medicare should be changed to a system where the government provides seniors with a fixed sum of money they could use either to purchase private health insurance or to pay the cost of remaining in the current Medicare program.” Fully 74 percent of white seniors said instead that “Medicare should continue as it is today, with the government providing health insurance and paying doctors and hospitals directly for the services they provide to seniors.” Among non-college whites, 63 percent said they preferred the current system, while only 26 percent backed Ryan’s approach. (Ryan’s plan also drew opposition not only from 66 percent of college-educated white women — consistently the most Democratic-leaning component of the white electorate — but even 60 percent of college-educated men, an audience usually receptive to anti-government arguments.)

Generally surveys find white women more resistant to changes in the safety net than white men (although the specific Congressional Connection Poll on Ryan’s plan didn’t show that pattern.) If Ryan’s plan remains a central focus through the fall, it would not be surprising if that debate widened the gender gap — potentially helping the Republican ticket with men most receptive to the sort of broad anti-government arguments Ryan unfurled in his announcement speech Saturday, but hurting it with white women.