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From NPR News, it's ALL THINGS CONSIDERED. I'm Audie Cornish.
ROBERT SIEGEL, HOST:
And I'm Robert Siegel. Last night's triple primary victory has further propelled Mitt Romney to the front of the Republican presidential race. Now that Romney has lengthened his lead, he's turning to President Obama. Here's Romney speaking today to the American Society of News Editors.
MITT ROMNEY: I'm running for president because I have the experience and the vision to get us out of this mess. We know what Barack Obama's vision of America is - we've all lived it these last three years.
SIEGEL: As NPR's Mara Liasson reports, the campaign is playing out in two dimensions - the Republican primary season continues as the general election begins.
MARA LIASSON, BYLINE: Rick Santorum told his supporters last night that it's only half-time, and it is true Mitt Romney has only 550 of the 1,144 delegates he needs to win. But as Republican strategist Ed Rogers points out, the outcome of the GOP race is now all but certain.
ED ROGERS: It's all over in the Republican primary. Romney is our nominee. Barring something unforeseen - an act of God, a meteor strike - there is no possibility that the Santorum campaign at this point in time will overwhelm the Romney campaign.
LIASSON: Now Romney has to get ready for a new kind of campaign - the general election against President Obama. He's got to repair the damage from a primary that John McCain just this morning called disastrous for Republicans. Romney's enlisted the aid of his wife, Ann, to reach out to women voters. Polls show women turning back to the Democrats after months of hearing Republican calls to defund Planned Parenthood or limit access to contraceptives. Ed Rogers...
ROGERS: That's where Romney has really got to direct some attention in the near term to make sure that a sizeable portion of suburban women don't harden their opposition to the Republican point of view and therefore toward Romney.
LIASSON: President Obama has had a head start on the general election for the simple reason that unlike Romney he didn't have a bruising primary. In the last 50 years, every incumbent that faced a significant primary challenge lost - everyone who didn't was re-elected. Former Republican strategist Dan Schnur, who runs the Jess Unruh Institute of Politics at the University of Southern California, says without a primary President Obama hasn't had to pander to the left wing of his party.
DAN SCHNUR: Barack Obama, by not having to run in a primary, he can talk about cutting the corporate tax. He can talk about the need for continued oil drilling. He can position himself pretty close to the political 50-yard line. Romney has been fighting, you know, the fight on the right. Now, he needs to move to the center.
LIASSON: And he's trying. In addition to reaching out to women, Romney is changing his tone on immigration, telling voters in Wisconsin this week that he supports legal immigrants. Republican strategist Whit Ayres says Romney also has to do more than just attack the president.
WHIT AYRES: Governor Romney has the elements of a compelling alternative vision, but he has yet to paint the full picture. He's going to have to argue in a very concrete way that his background and his experience can translate to a better outcome for people who are scared to death about the state of our economy and the incredible debt racked up by this administration.
LIASSON: In the past, incumbent presidents have been able to use this period - before the official end of their rivals' primary - to define the eventual nominee before he has a chance to define himself. Bill Clinton did it to Bob Dole. George W. Bush did it to John Kerry. President Obama is trying to do it to Mitt Romney, but it might not work because, says Democratic strategist Tad Devine, unlike those other challengers, Romney has an important advantage - the resources to define himself.
TAD DEVINE: At the beginning of March in 2004 when Senator Kerry effectively won the nomination, we had $2 million in the bank, and President Bush had $100 million in the bank. Romney doesn't have that problem. Particularly with the new rules of superPACs, he's going to be able to bring a lot of resources to bear in the battle that lies ahead in the next few months.
LIASSON: That battle is already personal, polarizing and ideological. Last night, Romney said President Obama wants a government-centered society. Yesterday, President Obama said Romney's fiscal policies are social Darwinism. Both candidates - the vulnerable incumbent and the weakened challenger - are trying to define each other as the general election campaign gets underway. Mara Liasson, NPR News, the White House. Transcript provided by NPR, Copyright NPR.