Over the past year, Wisconsin has produced more than its share of Republican heroes. Governor Scott Walker faced down public-employee unions, and faces a well-funded recall attempt as a result. Newly minted U.S. senator Ron Johnson has been a leading voice against excessive debt and the dangers of Obamacare. Conservative Wisconsinites want Representative Paul Ryan elected president of the world — and if another planet is discovered with life on it, they would elect him president of that one, too.

It stands to reason, then, that the Republican presidential primary to be held on April 3 is a mere undercard to all the other action in the state — most notably the Walker recall on June 5. But even though the presidential race may not be on the tip of every cheesehead’s tongue, the state GOP will grant someone its 42 delegates next Tuesday. And come November, it will be one of the handful of states that determines who will be filling out the official presidential March Madness bracket next year.

As noted by Milwaukee Journal Sentinel election guru Craig Gilbert, this is the first time in 32 years Wisconsin will have the chance to make a difference in a competitive GOP primary. And according to a poll released yesterday by Marquette University, Wisconsin primary voters are likely to help Mitt Romney edge closer to the nomination: Among them, Romney leads Rick Santorum 39 percent to 31 percent.

Romney’s lead in Wisconsin is a new development. Between February and March, Romney’s support grew from 18 percent to 39 percent, while Santorum’s has dropped slightly, from 34 percent to 31 percent. Perhaps this is due to the $2 million Romney and his allies have used to blanket the state’s airwaves with anti-Santorum messages (Santorum has spent less than $100,000). It could also be that the state’s voters have bought into the narrative of Romney’s inevitability, or that they are unconcerned about his famous ideological flexibility. (When the poll asked Republicans what was the most important quality they were seeking in a nominee, only 18 percent answered “is a true conservative”; 30 percent answered “has strong moral character,” and 26 percent answered “has the right experience to be president.”)

But to understand the presidential primary in Wisconsin without incorporating the recall election’s politics is like buying unscented perfume. The two are linked — and may offer a clue as to why Romney is surging.

Romney was the first candidate to publicly support Scott Walker, which is a prerequisite to being taken seriously as a Republican in Wisconsin. In a radio appearance last Wednesday, Romney said of Walker:

I support him and support his efforts. . . . I have no reason to be critical of any of the steps or the process that he has pursued because I’m frankly not there and in his position. So I can only tell you that I think his effort to try and rein in the excesses and to try to give the state a more solid financial footing makes a great deal of sense and I support him.

On Tuesday night, Santorum jumped into the Walker sweepstakes, telling a local television reporter that he will be having announcements over the next few days as to how he will be helping Walker’s recall-election effort. Santorum had to do something to stop the bleeding, as Romney is blanketing the state with robocalls accusing him of being soft on labor. “As if we didn’t have enough to worry about,” a pleasant young woman says in one recorded call, “I learned that Rick Santorum repeatedly supported Big Labor and joined with liberal Democrats in voting against collective-bargaining legislation during his time in Washington.”

Both candidates are trying to cozy up to the “Walker aura,” as both are viewed skeptically by the state’s Republicans. According to the Marquette poll, Romney’s favorability among Republicans stands at only 55.3 percent; Santorum’s favorability is only slightly lower at 52.8 percent. Conversely, Scott Walker’s favorability among Wisconsin Republicans is 85.1 percent. A similar 85.9 percent of Republicans approve of the job Walker is doing as governor. (If Paul Ryan’s approval numbers were tested, it would show his approval to be 185 percent among Wisconsin Republicans — which seems impossible, until you realize he’s that good with numbers.)

Further, the rolling recall carnival will affect the way candidates have to campaign in Wisconsin, as they will be subjected to experiences unseen in other states. When Ann Romney visited a Madison-area diner last week, a local Democratic legislative candidate greeted her with a stuffed dog strapped to the roof of her car. Another liberal activist tried to push through and hand her an Etch A Sketch. “Occupy” protesters lined up to picket against Scott Walker can now easily pull double duty and incorporate anti-GOP presidential chants. (“Come for the Walker protest! Stay to call Santorum a racist!”)

Whichever candidate emerges will need to eliminate Barack Obama’s 16-point 2008 margin of victory in Wisconsin. (George W. Bush lost the state by less than one point in both 2000 and 2004, although the state hasn’t voted for a Republican presidential candidate since Ronald Reagan’s landslide in 1984.) Among the current candidates, Romney seems to be making the most headway, shrinking Obama’s 15-point head-to-head lead in February to only five percentage points in March.

For Romney, the key will be to support Walker enough in the primary to win Wisconsin’s delegates, but not so much that it costs him blue-collar, conservative union-member votes in November. If he loses those households, not even a Vice President Paul Ryan could help him in Wisconsin in the fall.

— Christian Schneider is a senior fellow at the Wisconsin Policy Research Institute and a co-author of the Campaign Manager Survey.