What does Wisconsin get when it crosses the recall of Governor Scott Walker with a Republican presidential primary? The serious answer: a massive infusion of Super PAC and other outside money into the state.

Most of the state has been focused on Walker's campaign to hold onto his job for the past several months, but in advance of Wisconsin’s April 5 presidential primary, Romney, Santorum, Paul and Gingrich are competing for a little bit of attention -- and for Wisconsin's 42 delegates.

And the candidates' Super PACs are doing most of the spending.

Romney Super PAC Peels off $2 Million to Slap Santorum

Flush with cash, Romney and his Super PAC have been running ads for weeks to soften the state (and, lately, fight "Etch-a-Sketch"-creep). Restore Our Future [3], a Super PAC run by former Romney aides, has spent more than $2 million [4] on ads that began in early March -- more than double the $747,000 spent by the campaign. The Super PAC’s lead contributors feature a hedge fund manager, John Paulson, who Politico [5] describes as making a fortune betting on the collapse of the housing market, and Bob Perry [6], who was behind the infamous "Swift Boat Veterans for Truth" ads that in 2004 accused Democratic presidential candidate John Kerry of puffing his war record. According to Bloomberg, the Super PAC's ads are produced by Larry McCarthy, notorious for the racially-tinged "Willie Horton" ad that undermined Michael Dukakis's presidential campaign.

True to its contrarian backers, Restore Our Future functions as a kind of nasty twin to Romney. The Super PAC ads attack opponents [7] where Romney's official "and I approved this" campaign ads [8] seek to elevate his standing.

For example, the Super PAC’s anti-Santorum ad that has run some 2,000 times in Wisconsin alleges that Santorum doesn't support national right to work legislation. Although the ad isn't tailored to Scott Walker supporters, it echoes a conservative boilerplate issue of opposition to unions and collective bargaining. (Santorum's response is that states should pass right to work legislation, not the federal government.) Overall, Restore our Future has lived up to its reputation as a candidate "death machine," [9] spending more than $36 million [10] nationally to undermine Santorum's and Gingrich's campaigns.

Romney has also thrown his support behind Walker. On March 28, Romney told Wisconsinites [11], "I support the governor in his effort to reign in the excesses that have permeated the public sector union and government negotiations over the years." Romney said, "Governor Walker is, in my opinion, an excellent governor."

Santorum's "Red, White and Blue" Rips Romney

Santorum's Super PAC, The Red, White and Blue Fund [12], parried [13] on March 27 with a $471,000 ad purchase [14] for broadcast and cable television (more than the $228,000 the campaign is estimated to have spent). The ad zooms in on Romney's face, with the narrator suggesting a liberal's DNA, and then zooms out again to find Obama's profile next to Romney. The narrator declares that Romney created the "blueprint for Obamacare," supported the Wall Street bailout, and raised taxes in Massachusetts.

Santorum appears to have left it to freelancers to embarrass Romney on his aide's depiction of the Romney campaign as an "Etch a Sketch." Protestors [15] turned up outside a downtown Middleton pie shop on March 24 with the famous red screens to wave at Romney's wife, Ann.

The Red, White and Blue Fund, for its part, is funded most prominently by Wyoming investment banker Foster Freiss [16], who is also a major investor in right wing journalist Tucker Carlson's Daily Caller. But the fund is significantly smaller than Romney's Super PAC -- the Red, White and Blue Fund reportedly has less than half a million dollars remaining, compared to Restore Our Future, which is sitting on $16.3 million in reserves [17] as of February 21.

Santorum has also sought to attract Walker supporters: "Of course I’m looking forward to doing whatever I can (to aid Walker)," Santorum says [18]. "I think we’re going to maybe try to swing by throughout the week one of the call centers here to try to help the governor and his effort. As someone who understands tough political fights and someone who stood up to the establishment as this governor has done, we want to give every bit of support we can to someone who has the courage to confront the tough issues. And it shows you we're willing to do the same kind of thing in Washington, D.C."

Gingrich and Paul Backers Hold onto Their Wallets

Newt Gingrich and Ron Paul have not announced media buys for Wisconsin and appear to be keeping communications mostly personal in their campaigning to date. Gingrich's current wife, Callista, the author of a best-selling children's book that features a patriotic elephant named Ellis, is originally from Whitehall, Wisconsin. She has been speaking on Gingrich's behalf while his campaign faces a spiraling loss [19] of staff and funds. Much of Gingrich's support had come from the Super PAC Winning our Future [20], which is funded prominently by infusions from casino mogul Sheldon Adelson. The Super PAC has already spent more than $16 million [21], but Gingrich's campaign is otherwise said to be in the red.

Gingrich also supports Wisconsin’s governor -- but only if Walker wants his help. "Scott Walker's fight in Wisconsin has made him a national leader on issues important to Republicans. Of course I would campaign for him,"the former speaker said [22]. "But I would only do that if he asked me. If he didn't want supporters coming in from outside the state, I'd respect that."

It does not appear that Ron Paul or the Super PACs supporting him -- such as Endorse Liberty PAC [23], which is funded largely by Peter Thiel, the founder of PayPal -- have spent on ads in Wisconsin. However, Paul appeared at University of Wisconsin-Madison on March 29 and fired up [24] a few thousand college students. Paul also had kind words for Walker: "He's trying hard to change things, I think in a positive way," Paul said. When asked about Walker's plans to limit collective bargaining rights, Paul said, "I think the market should dictate everything."

Polling puts Romney well ahead of the field, with a Rasmussen poll [25] showing him with 46 percent of likely Republican voters, while Santorum has 33 percent, Paul 8 percent and Gingrich 7 percent.