— To watch Mitt Romney campaign across Wisconsin the past few days has been to wonder whether the Republican primary is still going on.

Romney shifted subtly into general election mode. He overhauled his rhetoric about President Obama and offered a new slogan: “Obama’s Government-Centered Society.” He auditioned a potential running mate, Rep. Paul Ryan (R-Wis.), who has developed chemistry with Romney over four straight days together on the campaign trail. And Romney hinted at how he hopes to smooth over his positions on issues such as birth control and immigration to win over voters this fall.

At the conclusion of a speech in Appleton, Wis., on Friday, Romney asked voters to join him and “walk together this Tuesday — and take another step every day until November 6th.”

But what about Rick Santorum?

Romney certainly doesn’t seem to be thinking too much about him — at least not since arriving in Wisconsin. Instead, Romney has used his busy campaign swing through the state in advance of Tuesday’s primaries here and in Maryland and the District to preview how he may campaign later this year. At one stop, Romney even ticked through his agenda for his first day in the White House.

First, though, Romney must finish off Santorum, as well as former House speaker Newt Gingrich and Rep. Ron Paul (Tex.). And Santorum insists he will keep fighting, saying Monday that a long nominating contest is healthy and that a floor fight at August’s GOP convention would be “exciting” for Republicans.

Nonetheless, Romney is trying to seize the mantle of the presumptive nominee, framing the general election contest in appearances across Wisconsin as a battle between “very different visions” to restore America’s promise. And not only with regard to the sluggish economy, but also to the nation’s standing in the world.

“This president is going to be campaigning saying that he’s doing a great job. Do you know that he actually believes that he’s doing a great job? He said the other day that he’s doing an historically great job, like Lincoln, L.B.J. and F.D.R. And this was not said on ‘Saturday Night Live.’ He believes that. How can that be?” Romney said Sunday in Middleton, Wis., a line he repeated at nearly every stop the past few days.

Romney now acknowledges that the country’s economic conditions are improving, but he still blames Obama for not asserting enough leadership to lift the country out of the recession faster.

“He did not cause the recession, but he did not cure the recession,” Romney said. “He did not cause the kind of turnaround we wanted and we needed so desperately. He’s going to try and take credit for improvement, and improvement will occur. Markets come back, small businesses start to grow -- that will happen in spite of what he’s done.”

The fault lines for the Obama-Romney fight are becoming clear, as the White House has begun directly engaging the former Massachusetts governor. Last week in Iowa, Vice President Joe Biden attacked Romney and said he would bring the economic recovery “to a screeching halt” if he wins the White House.

“Look, folks, we have a choice in this election between our philosophy that believes manufacturing is central to our economy and their philosophy that scoffs at it, between our philosophy that says there is nothing out of touch about fighting for the future of the middle class by creating manufacturing jobs — and their philosophy says if the folks at the top do well, everything else will do well,” Biden said in the speech.

On the campaign trail, Romney’s aides now talk openly about the general election campaign while they are beginning to staff up at his Boston headquarters.

Romney’s advisers are starting to size up possible vice presidential contenders, with some paying close attention to Ryan, the House Budget Committee chairman who has built a passionate following among fiscal conservatives. After observing them toot each other’s horns at town hall meetings and pick up fried cheese curds at Culver’s, one adviser noted the “chemistry” between them.

When Ryan introduced Romney in Middleton, he explained what some see as oddities as Romney’s “upper-Midwest earnestness.” Then Romney joked about the youthful Ryan being just 10 years old when Ronald Reagan ran for president in 1980, to which Ryan said, “I did have a Reagan bumper sticker on my locker in the third grade.”

“This guy was born conservative!” Romney said.

After their playful banter, Romney pulled back the curtain a bit on his general election strategy. He said he believed Obama would “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.”

But he acknowledged the challenge before him to convince women and Hispanic voters to support him after he took stances on birth control and immigration that some independent voters might view as polarizing. A Gallup/USA Today poll in 12 general election swing states showed Romney trailing Obama among women voters by 18 percentage points.

“We have work to do to make sure we take our message to the women of America so they understand how we’re going to get good jobs and we’re going to have a bright economic future for them and for their kids,” Romney said. “And make sure that these distortions that the Democrats throw in are clarified and the truth is heard.”

Romney may not have helped himself a day earlier, however, when he said at a gathering of Christian conservatives that he would “protect the sanctity of life” and “defund Planned Parenthood” — remarks that Obama’s campaign has signaled it will use to pry women voters away from Romney.

Romney may have a similar problem courting Hispanic voters this fall, considering he voiced hard-line stances on immigration in some debates last fall.

“We are going to have to make sure as we talk to Hispanic voters that we say, ‘We are not anti-immigrant,’” Romney said in Middleton. “We are pro-immigrant. We are the party that loves people coming into this country as immigrants, bring skills and knowledge and culture and values.”