Steve Helber/AP Photo

As Paul Ryan love fests go, Wisconsin's Republican Senate primary might put his national roll-out to shame.

Since well before Mitt Romney introduced the Wisconsin congressman as his running mate on Friday, with the USS Wisconsin and a throng of cheering supporters in Norfolk, Va. as backdrops, candidates in Ryan's home state have been jockeying for super-fan status.

On Tuesday, Wisconsin Republicans will decide a multi-way Senate primary, the winner of which will run against Democratic U.S. Rep. Tammy Baldwin in November. As in primaries across the country, Ryan's budget plan is orthodoxy among Republicans.

The top three Republicans in this race all back Ryan's budget and Medicare reforms. Emphatically, in fact.

Former congressman Mark Neumann has praised it. Former governor and Health and Human Services Secretary Tommy Thompson has promised, repeatedly, to pass it. When Ryan introduced it in March, businessman Eric Hovde began airing a radio ad in its support. The three candidates attended a rally in Wisconsin on Saturday, as Ryan made his debut as VP candidate, and all lavished praise on him.

In a tight race, where polls have shown Hovde and Thompson as the leaders, each has sought an edge by clamoring to back Wisconsin's hometown budget hero.

None of this is very unusual, as GOP candidates elsewhere have backed Ryan's Medicare overhaul. In competitive races in Indiana, Missouri, and North Dakota, GOP candidates are on the record supporting Ryan's 2011 and 2012 budgets. In Virginia, former Sen. George Allen embraced Ryan over the weekend.

In New Mexico and Montana, GOP candidates have opposed Ryan's budgets, and have been put on the spot in 2012. Former New Mexico congresswoman Heather Wilson, who never had to vote on a Ryan plan, voiced unspecified "concerns" with his health-care provisions, unwilling to say whether she opposed or supported his budgets outright, at a briefing with reporters in Washington, D.C. in July. In Montana, the state GOP has run a TV ad touting Rep. Denny Rehberg's opposition to Ryan's budget.

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Once upon a time, Ryan's budget was controversial, a measure of tea-party extremity. What happened?

Soon after Ryan made a splashy introduction of his budget and Medicare proposals in 2011, Democrats flipped a GOP-held seat in a New York special election by running against his plan. (It helped that its previous occupant resigned from Congress after it turned out he sent half-naked photos of himself from his phone and used to cruise the personal section of Craigslist.) It foreshadowed more controversy over Ryan's ideas and suggested that maybe his Medicare reforms were a political loser.

Republicans kept it at arm's length. House Speaker John Boehner was reluctant to embrace it, and former House speaker Newt Gingrich, when asked about the plan, began his answer, "I don't think right-wing social engineering is any better than left-wing social engineering."

At the time, conservatives were emboldened by the GOP's ascent to the House majority in 2010's midterm elections, and enough support coalesced around the Ryan plan that Gingrich was forced to call Ryan and apologize, and to later explain that he had been talking about something else when he uttered the comment - and that he did not, in fact, view Ryan's Medicare plan as "right-wing social engineering."

As Ryan sparred with President Obama over the plan, and as Republicans engaged in a series of spending stalemates with Obama that threatened to suspend the federal government and downgrade U.S. credit worldwide - and as Boehner failed to wrangle his party into a compromise with Obama in a late night of arm-twisting - it became clear that the GOP's fiscal positions had become calcified. Fast-forward to 2012, as tea-party Senate candidates have defeated less conservative opponents in Nebraska, Texas, and Indiana. Conservative pressure on Republicans candidates is still strong.

Nowadays, it's much easier for a Republican candidate to support Ryan's budget and Medicare plan … as long as voters pay attention to what's in it. Ryan's 2011 plan, the controversial one for which he became known, entailed a near-voucherization of Medicare. His 2012 version, coauthored by Democratic Sen. Ron Wyden of Oregon, only presents that voucher-esque system as one option for seniors, who could also enroll in Medicare as a fee-for-service health-coverage plan, which is how it operates today.

It's clear that when people say "the Ryan Plan," the distinction between its 2011 and 2012 iterations has been lost, despite the major differences. For instance, aides for two Wisconsin campaigns did not know whether their candidates backed the 2011 plan or not.

In Wisconsin, as in the presidential race and down-ticket campaigns across the country, GOP candidates by and large back "the Ryan Plan," which passed the House with support from all but five Republicans. But in 2012, that doesn't mean quite the same thing.