By MICHAEL FALCONE ( @michaelpfalcone ) and AMY WALTER ( @amyewalter )

GREEN BAY, Wisc. - Mitt Romney and Rick Santorum trekked around Wisconsin over the weekend like two men on a very different mission.

Ever since his speech on Friday in Appleton, Wisc. in which he shook off any references to his opponents and pivoted to the fall battle with President Obama, Romney has looked more comfortable and more confident on the stump than at just about any other time during this primary.

Yesterday - April Fools Day - at a pancake breakfast in Milwaukee he even joked about how his campaign staff had pranked him into thinking he was about to address an empty room. But later in the day at a campaign stop just outside Madison he offered a prediction that was no joke:

"This president can't run on his record," Romney said. "And so he's going to try in every way he can to divert to some other kind of attack and try to have people disqualify our nominee, which will probably be me, instead of talking about where we've been, and where we're going as a nation."

Romney's message that he is now the probable nominee was not well-received by Santorum, who, despite the likelihood of losses in the Wisconsin, Maryland and District of Columbia primaries tomorrow, spent the weekend warning voters against "cutting this short and getting the wrong candidate."

"Why is he spending $4 million in Wisconsin if the race is over?" Santorum said of Romney Sunday afternoon at an event near Green Bay. "If it's over and you know, there's no chance, then why is he bothering even campaigning anymore if it's over?"

Santorum's argument: "We aren't even at halftime folks, not even half the delegates have been selected in this race."

The former Pennsylvania senator's campaign team still rails against the notion of Romney's inevitability, but even their own candidate seemed to set a specific bar for continuing the fight. In an appearance on NBC's "Meet The Press" yesterday, he said: "We have to win Pennsylvania and we're going to win Pennsylvania. I have no doubt about that."

And with Romney creeping up on Santorum in the recent polls in Pennsylvania, which holds its primary on April 24, his statement yesterday may have sealed his fate as a candidate.

"I think Pennsylvania is going to be really important for us," his campaign manager Mike Biundo said in an interview with ABC News on Sunday. "I wouldn't be doing myself or the senator justice if I said any different."

Instead of staying in Wisconsin tomorrow night, Santorum will hold his election night party in Pittsburgh, which is also a sign of how the campaign is assessing their own chances in the Badger State.

But for the last few days, Santorum has been campaigning with Iowa-like intensity. Today he holds five events throughout the state and on Wednesday he has another busy day of events planned to kick off his Pennsylvania effort.

But Santorum's going to have company. Over the next couple of weeks, Romney is going to try to do what Santorum failed to do Michigan - beat his opponent on his own "home" turf. Romney knows that a win in Pennsylvania would end a primary that already looks over.

SANTORUM'S LAST-MINUTE MESSAGE. On the campaign trail this weekend there were few signs that Rick Santorum was ready to ease up in his criticism of Mitt Romney. And this morning, on the eve of the Wisconsin primary, his campaign released a new television ad linking Romney to President Obama. "What if I told you this man's big government mandating health care included $50 abortions and killed thousands of jobs, would you ever vote for him? What if I told you he supported radical environmental job-killing cap and trade and the Wall Street bailouts? And what if I told you he dramatically raised taxes and stuck taxpayers with a $1 billion shortfall?" the ad's narrator says. "One more thing, what if I told you the man I'm talking about isn't him," the narrator says as a photo of a grimacing President Obama flashes on the screen and then dissolves into a photo of Romney. "It's him."  WATCH: http://bit.ly/HAYug4

 

A JAKE TAPPER EXCLUSIVE: ONE-ON-ONE WITH BILL CLINTON:

-ON MITT ROMNEY'S ETCH A SKETCH: IT'S 'WHAT HE'S GOT TO DO'  Mitt Romney, the presumptive Republican presidential nominee, currently faces a dynamic similar to the one President Bill Clinton faced during his first presidential run 20 years ago: a long, bruising primary, driving up his unfavorable ratings. Clinton turned it around. Can Romney? "I doubt it," the former president said in an interview with ABC's Jake Tapper on Sunday. "Mr. Romney has a different challenge than I did," Clinton said. "Even though he had a bruising primary and higher negatives and I did too. Mine was just one long character attack. It was a personal attack on me. You know, 'You shouldn't have this guy be president.'" Clinton was able to turn it around, he said, because "the American people are inherently fair. I named Al Gore. We reintroduced our economic plan. Then we reintroduced ourselves to the American people. But we never had to change what we were saying from primary to the general. The problem that Governor Romney has, is his character attack was 'You don't really know what he believes. He did this, he says that.' "He started this campaign in the aftermath of that tea party victory in 2010," Clinton said, "when all the people on the far right of the Republican party actually believed a majority of the voters had embraced the specific things they were saying. So it created a horrible dilemma for Romney. And the poor man who got in trouble for the Etch-a-Sketch remark. That's like the saying, 'There is nothing more damaging in politics than telling the truth.' I mean, the truth is, that's what he's gotta do." http://abcn.ws/HO7R82

-ON TRAYVON MARTIN. Clinton said the "tragedy" of the killing of Trayvon Martin should cause a re-thinking of the "Stand Your Ground" law. "There are different stories being told," the former president said, "so the first thing I have to say is that it's important to find out the facts." Clinton continued "but to me, beyond the incredible personal tragedy- this young man was not armed, he clearly presented no threat to anybody's life - is, the most important thing I've read was from the former police chief in Florida in the community, he was one of many law enforcement officers testifying against that Stand Your Ground law. And he said, you know this is going to create all kinds of problems. And it's going to be almost impossible to prove what was in someone's mind when a certain thing happened." http://abcn.ws/HFCT5a

-BACKSTORY: From ABC's Jennifer Wlach: This weekend over 1,000 college students from around the world descended upon Washington D.C. to participate in the 5th Annual Clinton Global Initiative University, or CGI U-a summit started by former President Bill Clinton in 2008 to inspire the youngest generation of Americans to lead a life of service. The former President commended the ingenuity of the CGI U participants-saying the entire summit benefits from a dichotomy of groups. "There are the young people who are always idealistic and always have good ideas. Then there are the young people who are disillusioned with government or with the private sector, who think, 'Okay, I wanna take things in my own hands. Start my own organization. Do something that makes a difference for the grassroots up,'" Clinton said. "And we had both types of young people here. It was very interesting." http://abcn.ws/H6RZC2

More from Jake's interview with Clinton: He handicaps Romney's Chances in the general election. WATCH: http://abcn.ws/HB6r4Y

 

"THIS WEEK" REPLAY:

-PAUL RYAN ON GAS PRICES. Rep. Paul Ryan said yesterday on "This Week" that the idea of releasing oil from strategic reserves to drive down domestic gas prices was "political pixie dust in an election year." "I call it the political pixie dust in an election year.  It really doesn't do a lot," Ryan told ABC's George Stephanopoulos  "Instead of begging the Saudis to sell us more of their oil, what our budget does is says let's go and explore more of our own oil." I asked Ryan about the idea of releasing oil from strategic reserves after Rep. Chris Van Hollen said that "the president has reached out to other oil-producing countries around the world.  And they have got a strategy now to get more oil on the market.  That should drive down prices.  It should begin to pop that speculative bubble." The Obama administration had declined to outline specific action it is taking in this regard even as France said earlier this week that it is considering tapping its reserves as part of an effort by the United States to lower the price of oil. Ryan, a congressman from Wisconsin, suggested that access should be granted to "oil that is locked on public lands by President Obama." http://abcn.ws/Hy3qgC

-ANN COULTER ON MARCO RUBIO AS V.P.: A 'MISTAKE' While pundits, politicians and prognosticators have tapped Florida Sen. Marco Rubio as one of the most likely GOP vice presidential picks, conservative commentator Ann Coulter warned yesterday that such a choice would be a "mistake." "I think that would be a mistake because the same people who loved Rubio loved [former presidential candidate and Texas Gov.]Rick Perry," Coulter said Sunday during the "This Week" roundtable discussion. "I want someone who's been a bit more tested." As the rising star of the Tea Party and a Hispanic from the delegate-rich state of Florida, Rubio would fix Romney's two biggest problems: enthusiasm among the Republican base and lackluster support from Hispanics, argued conservative commentator George Will. http://abcn.ws/HyFR99

In case you missed Sunday's edition of "This Week," watch the full episode and clips here: http://abcnews.go.com/ThisWeek/

 

THE BUZZ

S.C. GOV. NIKKI HALEY SAYS SHE'D TURN DOWN VEEP JOB. In a recent interview at the governor's mansion in Columbia, S.C., Gov. Nikki Haley told "Nightline's" Cynthia McFadden the sign has been there since day one of her administration. "I want everyone who comes in - staff, legislators, constituents - to know from the outset that's how things work here," she said. It can make her a tough boss at times she admits, but, she says, an effective one. A Tea Party favorite endorsed by Sarah Palin during her gubernatorial race in 2010, Haley's endorsement in the Republican primary was a highly coveted one. The South Carolina governor came out early for Mitt Romney, criss-crossing the state with him in the weeks before the state's January primary. Despite her stalwart campaigning on his behalf, Haley claims she has no interest in being his running mate. If offered the vice presidential slot, Haley said she would not take it. "I'd say, 'Thank you, but no,'" she said. "I made a promise to the people of this state. And I think that promise matters. And I intend to keep it." But the governor fell short of delivering a South Carolina win to Romney. Instead the GOP presidential candidate suffered a substantial defeat in the Palmetto state, falling 13 percentage points behind Newt Gingrich. Haley brushed off Romney's loss. "South Carolinians are strong, independently-minded people," Haley said. "At the end of the day, they make their own decisions. And I respect them for that. And I welcome that. And I told him that from the very beginning." http://abcn.ws/HeND61 Watch the full interview with Gov. Nikki Haley on "Nightline" tomorrow.

ROMNEY GETS PUNKED. The joke was on Mitt Romney yesterday when his staff played an April Fool's trick on him, directing him to speak to an empty room instead of the packed ballroom where his event was actually scheduled to be held, shocking him with a non-existent audience just days before the Wisconsin Republican presidential primary, ABC's Emily Friedman notes. "This is a morning I'm not going to forget anytime soon," said Romney, who was introduced by Rep. Paul Ryan and Sen. Ron Johnson, who endorsed him earlier today. "You know it's April Fool's Day. I forgot. They turned me into the April Fool this morning, those guys. Your senator, your congressman," Romney told the crowd that was gathered for a pancake brunch at the Bluemound Gardens event space. "Downstairs is a room just like this one, and it was all set up." Romney said the black curtain that usually shields him from the crowd before he enters was set up, as was the tape on the floor instructing him and the introducers where to stand. By all accounts, Romney believed he was readying to address the breakfast crowd. "They're all standing there. Paul Ryan goes out first, all right, and this is downstairs, there's not a person in the room, and my staff says to me, 'There's a small - It's a small - We didn't get much of a turnout this morning, it's really small, but it will be OK, it will be OK,'" Romney said. "And so I hear Paul Ryan goes out, gives the same introduction, what he just said. He's down there, 'And so now, let's welcome Ron Johnson, and Mitt Romney, the next president of the United States.' "And so the two of us go out there and it's completely empty," Romney said. "There's nobody there. I thought, oh, boy, this is going to look really bad on the evening news, let me tell you." http://abcn.ws/H8sktJ

BIDEN ATTACKS ROMNEY, GOP AS 'OUT OF TOUCH' Vice President Joe Biden "can't remember" a candidate as out of touch with the American middle class as Mitt Romney, he said in an interview that aired yesterday, ABC's Matthew Larotonda reports. The claim is not new to the Obama campaign, but in a CBS interview broadcast this morning the vice president's remarks advertise the characterization as the Democrats' new primary line of attack. "I can't remember a presidential candidate in the recent past who seems not to understand by what he says what ordinary middle class people are thinking about and are concerned about," Biden said. "Out of touch" finger-pointing is certainly not an original idea in politics. Democrats and Republicans have long sought to paint the other side as aloof to the values and everyday hardships of Americans. During the height of the 2008 campaign, attack ads from both sides looked like they were written by the same author. But the recent focus from the Obama campaign  is intended to dovetail with weeks of debate over the "Buffet Rule," a bill the White House is pushing that would mandate Americans making more than $1 million a year pay at least the same tax rate as people in the middle class. The GOP maintains the president is engaging in class warfare. http://abcn.ws/Hd8lmP

 

IN THE NOTE'S INBOX:

-DEMOCRATIC SUPER PAC LINKS ROMNEY TO BIG OIL. "Priorities USA Action today released a television ad 'Romney's Big Oil Trail' to expose the true motivations of big oil's attacks on President Obama - to elect Mitt Romney who stands to protect big oil's profits at the expense of middle class Americans. 'While President Obama is taking serious action to make America less dependent on dirty and dangerous sources of Middle East oil and create clean energy jobs here at home, Mitt Romney and the oil companies bankrolling his campaign are profiting from high gas prices politically and financially,' said Paul Begala, Senior Advisor for Priorities USA Action. The ad will run both on television and online in Colorado, Florida, Iowa, Michigan, New Mexico, Nevada, Ohio and Virginia." WATCH: http://bit.ly/HgxiOW

 

WHO'S TWEETING?

@markknoller : Today at the WH: Pres Obama hosts a joint summit with his counterparts from Canada & Mexico: PM Stephen Harper & Pres Felipe Calderon.

@HotlineAlberta : Milwaukee Journal-Sentinel headline: "Gingrch weighs in on Obama, Wisconsin recall, American civilization"  #strong

@rickklein : Romney win in  #WIprimary would put exclamation point on a sentence that's ending anyway. my  @ABCWorldNews take: http://abcnews.go.com/blogs/politics/2012/04/world-news-political-insights-gop-race-winding-down-to-mitt-romney-win/

@mattklewis : McCain's '00 ad seems way tamer than Santorum's '12 version. McCain said: "[Bush's] ad twists the truth like Clinton." http://www.youtube.com/watch?v=UHoXkCprdL4

@RyanLizza : RT  @HotlineReid: Ron Paul has spent $496k per delegate, Romney has spent $118k, Santorum $50k, per  @MajoratNJ - http://decoded.nationaljournal.com/2012/03/gop-costperdelegate-madness-ro.php

 

PRIMARY STATE SPEED READ

by ABC's Chris Good

-Suburban Voters Will Dominate in Wisconsin. Good news for Mitt Romney, who has performed better among suburban voters in GOP primaries so far: The Milwaukee Journal Sentinel's Craig Gilbert points out that Milwaukee's suburbs will form the "pulsing heart" of the GOP electorate on Tuesday, although rural voters accounted for 40 percent of the primary electorate in 2008. Romney has visited only five Wisconsin counties to Santorum's 22, by Gilbert's count, but those five counties have the largest populations in the state. "Where [western Milwaukee suburb] Waukesha goes, so does the rest of the Republican Party-most of the time," state Senate Majority Leader Scott Fitzgerald tells the paper. http://bit.ly/HC4uTE

-Low Turnout Expected in Maryland. Wisconsin seems to have stolen the show in Tuesday's primaries, when D.C. and Maryland will also vote. The Baltimore Sun reports that low turnout is expected in Maryland, as the GOP presidential primary and the state's other voting contests have "largely failed to capture voters' attention." Perhaps seeking to remedy that, opponents of state Sen. David Brinkley, who is challenging U.S. Rep. Roscoe Bartlett (R), released audio over the weekend of a 2008 911 call from Brinkley's home after a domestic dispute. http://bsun.md/HxGPqN

POLITICAL RADAR:

-Mitt Romney is on the trail in Wisconsin a day before the primary. Romney and Congressman Paul Ryan will hold an event in Green Bay and a town hall at the Moore Oil Company in Milwaukee.

-Rick Santorum also campaigns in Wisconsin with stops in Shawano, Appleton, Menasha, and Oshkosh. Santorum ends the day at the Little White School House in Ripon, the birth place of the Republican Party.

-Newt Gingrich brings his message to Maryland hosting a rally at the Frederick Motor Company and delivering remarks at Hood College. Maryland holds their primary on Tuesday.

-ABC's Josh Haskell ( @HaskellBuzz)

 

 Check out The Note's Futures Calendar:  http://abcn.ws/ZI9gV

 

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