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

Republicans want to make this week all about President Obama's signature health care law.

Mitt Romney begins his day at a medical device company in San Diego, California, and his choice of venue is no accident. On the same day that the U.S. Supreme Court will hear arguments over whether to consider a challenge to the individual mandate, he will be talking about the need to repeal and replace "Obamacare."

Yesterday in Washington, Rick Santorum, used health care as a weapon against Romney, arguing that his rival's Massachusetts health care plan served as an inspiration for the Obama administration's version, which has become the leading symbol for Republicans of what they see as government overreach.

"Pick any other Republican in the country," Santorum said of Romney at South Hills Country Club in Franksville, Wisconsin. "He is the worst Republican in the country to put up against Barack Obama."

So far, Romney has managed to deflect such criticism, but with the issue of the constitutionality of health care front-and-center this week, Santorum is seeking to more forcefully tie his opponent to the Democratic-backed law. The former Pennsylvania senator plans to speak from the steps of the Supreme Court this afternoon.

But if Republicans want to frame contest in November around "Obamacare," and all it symbolizes, Democrats want to portray the Paul Ryan budget plan as a central example of GOP heartlessness.

In an interview yesterday on "This Week," President Obama's top strategist David Plouffe even went so far as to call it the "Romney-Ryan plan."

"If Mitt Romney's elected president, he'll rubber-stamp that budget," Plouffe said. "And here's what that budget is. It fails the standard - it fails the test of balance and fairness and shared responsibility."

And in advance of the vote in the House of Representatives on the Ryan plan, the Democratic Congressional Campaign Committee has released a new web video titled, "Standing Up For Medicare," feature actor Martin Sheen protesting the GOP's "attempt to end Medicare and give tax cuts to millionaires and special interests." WATCH: http://bit.ly/GQ181Q

SUPREME COURT PRIMER. From ABC's Ariane de Vogue: On Monday the Supreme Court will hear arguments on whether it is premature for the Court to consider a challenge to the individual mandate, a key provision of the Affordable Care Act, that requires almost every individual to buy health insurance by 2014 or pay a  penalty. At issue will be the Anti Injunction Act (AIA), a federal tax law that says, in essence, that a tax payer cannot challenge a tax, at a minimum, until it comes into effect.  If the Supreme Court eventually rules that the individual mandate triggers the AIA, the court will have effectively punted the constitutional debate concerning the individual mandate down the road. It will have found that no challenge to the mandate can be brought until it goes into effect, which is after 2014. Because lower courts have divided on whether the AIA applies, the Supreme Court dedicated 90 minutes of arguments to the issue. http://abcn.ws/H3yCpr

 

"THIS WEEK" REPLAY: MICHELE BACHMANN ON THE 2012 RACE. Former presidential candidate Rep. Michele Bachmann, R-Minn., said she believes the Republican party will unify behind the eventual nominee, and does not believe they will be hampered by the ongoing primary fight. "I think the quicker that the Republicans can unify behind our candidate and make Barack Obama and his failed policies the focus of this election, the better off we all will be, but the people need to decide," Bachmann told ABC's George Stephanopoulos on "This Week." Bachmann has not endorsed a candidate, and did not say whether Rick Santorum or Newt Gingrich should end their challenge to front-runner Mitt Romney. "Whoever the people choose, I will back that candidate, because I want mine not to be a divisive voice," Bachmann said. "I want to help unify the party and bring together the Tea Party element, the evangelical, and the establishment, and then reach out to independents and disaffected Democrats." http://abcn.ws/GS0DSQ

And, the "This Week" roundtable joined the roiling national conversation on the shooting death of unarmed Florida teenager Trayvon Martin, questioning the controversial "Stand Your Ground" law at the center of the case. WATCH: http://abcn.ws/GM7iwv

In case you missed it, watch George's full interview with Obama strategist David Plouffe and former presidential candidate Michele Bachmann: http://abcnews.go.com/ThisWeek/

 

VIDEO OF THE DAY: Reagan to Obama: A Front Row Seat. ABC's Jake Tapper and Sam Donaldson on what it's like to covering the White House. WATCH: http://yhoo.it/GQkmkT

 

THE BUZZ

SANTORUM GETS FEISTY WITH NEW YORK TIMES REPORTER. Rick Santorum grew heated and accused a New York Times reporter of distorting a statement he made in an earlier speech, even yelling "It's bulls-t" to him, ABC's Arlette Saenz reports. Jeff Zeleny of the New York Times tweeted, "I ask Santorum if Romney is 'worst Republican' to run. He says: 'Quit Distorting my words It's bulls-t.' He says he was talking health care" During the speech, as he railed against Mitt Romney for his healthcare plan in Massachusetts, Santorum said the former Massachusetts governor was the "worst Republican in the country" to take on President Obama. "Pick any other Republican in the country. He is the worst Republican in the country to put up against Barack Obama," Santorum said at South Hills Country Club. Santorum was asked by reporters to elaborate on what he meant by the categorization, and he insisted he was talking about the issue of healthcare. Santorum increasingly grew agitated with the first group of reporters asking him to clarify his statement. "On the issue of health care. That's what I was talking about, and I was very clear about talking about that. OK? C'mon guys, don't do this. I mean you guys are incredible," he said. "I was talking about 'Obamacare,' and he is the worst because he was the author of Romneycare." The exchange with Zeleny occurred towards the end of the ropeline as Santorum finished greeting voters. http://abcn.ws/GQwcsn

PRESIDENT OBAMA TO NORTH KOREAN LEADERS: HAVE THE 'COURAGE TO PURSUE PEACE.' ABC's Jake Tapper reports from Korea: President Obama paused during his speech to local college students in South Korea Monday to directly address the North Korean leaders across the DMZ, urging new dictator Kim Jong-un and his regime to pursue a different path. Saying he wanted to "speak directly to the leadership in Pyongyang," the president insisted that the United States was "committed to peace" and has "no hostile intent toward your country." That said, Mr. Obama scolded North Korea, saying its "provocations and pursuit of nuclear weapons have not achieved the security you seek, they have undermined it. Instead of the dignity you desire, you are more isolated. Instead of earning the respect of the world, you have been met with strong sanctions." Mr. Obama urged the North Koreans to change their ways. "Today we say, Pyongyang: have the courage to pursue peace and give a better life to the North Korean people," he said. The president also addressed Iran's pursuit of nuclear weapons, saying, "There is time to solve this diplomatically, but time is short." The speech, at Hankuk University of Foreign Studies, focused on the Nuclear Security Summit that kicks of later today, with the president heralding progress made in securing the world's vulnerable nuclear materials. http://abcn.ws/H6sb4a

WATCH Tapper's "World News" http://abcn.ws/H5RZPX and "Good Morning America" reports from Korea: http://abcn.ws/GS4j9u

 

WHO'S TWEETING?

 @danbalz : Santorum's says best for GOP is a short, 2-month general election to negate Obama's financial advantage, not quick end to nomination fight.

@AriFleischer : It was only a Romney aide who said Etch-A-Sketch. Now POTUS tells Russian President he himself is an Etch-A-Sketch.  #givemespace

@robertcostaNRO : I had breakfast w/ Santorum and a few other reporters this morning. Big takeaway: he's energized and ready to ride anti-O'care msg to Tampa.

@mlcalderone : Romney campaign manager "hasn't given a single on-the-record interview this entire cycle."  http://bit.ly/H4iQJv

 

PRIMARY STATE SPEED READ

by ABC's Chris Good

-Ron Paul's Missouri Dominance Continues. Ron Paul dominated the Missouri caucuses on March 17, and that continued over the weekend. St. Louis City and Jackson County, which encompasses Kansas City, held their caucuses a week later than most of the state, and on Saturday both went for Paul: in St. Louis, Paul's supporters elected a full slate of delegates to the state and congressional-district conventions, and in Jackson they selected about two thirds of the delegates available. The raucous St. Charles County caucus, which was shut down by police on March 17 amid a dispute between Paul supporters and the caucus chairman, has been rescheduled for April 10. http://bit.ly/GYxX8S

-Santorum Bowls for Votes. President Obama didn't have great luck at the lanes in 2008, but Rick Santorum flashed better form if this photo from the Fond du Lac Reporter proves anything. A greater abundance of blue-collar voters could help Rick Santorum win Wisconsin, and he sought them out at a bowling alley on Sunday, where he told about 300 supporters that Wisconsin "can be a game-changer" in the GOP race. Wisconsin offers Santorum the most friendly territory of any April 3 primary, when D.C. and Maryland will also vote.  http://fondul.ac/GS3qhf

- Ron Paul to Rally College Turnout in Maryland. After Louisiana's primary on Saturday, presidential candidates will turn some of their attention toward Maryland's April 3 contest, and the Baltimore Sun notes that Ron Paul will keep to his college-campus strategy with a town-hall at the University of Maryland's Ritchie Coliseum on Wednesday, while Newt Gingrich may step onto the floor of the Maryland General Assembly while campaigning in Annapolis on Tuesday.  http://bsun.md/GU1Bx2

 

POLITICAL RADAR:

-Mitt Romney holds a campaign event in San Diego, California before attending fundraisers in San Diego and Redwood City, Calif.

-Rick Santorum makes remarks outside the Supreme Court building in Washington, DC.

-Newt Gingrich campaigns at a GOP dinner tonight in Delaware.

-Ron Paul has no public events.

 

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

 

* Get  The Note delivered  to your inbox every day.

* For breaking political news and analysis check out The Note blog:  http://blogs.abcnews.com/thenote/ and ABCNews.com/Politics:  http://abcnews.com/politics