Pete Wehner believes that Ryan’s budget proposal is not much of a political liability:

To put it another way, four months after Ryan’s plan was introduced, it is nothing like the political liability many people thought it would be. In fact, the public’s attention remains focused on the debt and the deficit as well as job creation; “Mediscare” tactics haven’t gained any traction at all (but not for lack of trying by liberals). All this might change, but based on what we know at this juncture, Ryan and his plan are doing rather well.

Wehner’s evidence for this is mainly that movement conservatives and House Republicans have sided with Ryan, some of them were enthusiastically urging him to launch a presidential campaign, and Gingrich’s direct criticism of Ryan’s plan doomed his presidential bid. It seems clear that support for Ryan’s plan is now more or less required among movement conservatives, but the political danger from Medicare reform has never been that it would turn the conservative movement and House Republicans against its advocates. Gingrich was hardly a serious contender in the first place. It would be a mistake to see Gingrich’s collapse as proof that Ryan’s plan is popular. What Romney’s advisers seem to understand is that candidates proposing major overhauls to Social Security and Medicare will be vulnerable to attack, and these candidates will not fare very well with larger primary electorates that include many more low-information and non-ideological voters.

Ryan’s refusal to accept the role of pinata in the nominating contest suggests that he understood that his proposed changes to Medicare are incredibly difficult to sell to voters. Unlike Perry, Ryan can fall back on his previous support for expanding Medicare. That makes Ryan’s pretensions to fiscal responsibility easy to ridicule, but it allows him to blunt the attack that he simply wishes to do away with the program all together. Perry has denounced these programs, but it is not clear that he could defend his position very effectively. Ryan proposed a less ambitious change to Medicare than anything in Perry’s book, and even this appears to be politically toxic with the public. It may win Romney no friends with Ryan’s admirers, but Romney is betting that most primary voters want something very different from what Ryan boosters think they want. The bad news for fiscal conservatives is that Romney will most likely win that bet.