JACKSONVILLE, Fla. - To hear Newt Gingrich tell it, the dramatic conservative change he promises will begin even before he is sworn in as president in 2013.

"My goal would be by the end of that first day, about the time that President Obama arrives back in Chicago, that we will have dismantled about 40 percent of his government," he tells audiences.

Obama's health care bill? Repealed.

Legislation that toughened regulations on Wall Street after the economic collapse of 2008? History.

White House czars? Gone.

All this, and more, he pledges to get done before his head hits the presidential pillow for the first time.

It's characteristic Gingrich - bold and rich with details that lend credibility and evoke applause from supporters, yet sometimes based on assumptions that strain the imagination. It's all designed to make the case to Republican primary voters that he, not GOP presidential rival Mitt Romney, is capable of envisioning and then ushering in a new conservative age.

"We need someone who is going to fight back and doesn't back down," said Harry Berntsen, a Gingrich supporter, after listening to the former House speaker on Sunday at a sun-splashed rally at The Villages, a mammoth central Florida retirement community.

"I love the conservatism in him," added Sheary Berntsen, who, like her husband, wore a small sticker showing her support for Gingrich.

As he has done elsewhere, Gingrich outlined his Day One scenario on Monday for a small audience in Jacksonville, Fla., as he embarked on a final, full day of campaigning on the eve of Florida's Republican presidential primary.

The polls make Romney a heavy favorite in the state, dampening Gingrich's hope that his upset victory in South Carolina on Jan. 21 portended a steady rise. Already, Gingrich is pointing toward caucuses in Nevada and Minnesota in early February, followed by a showdown in Arizona at the end of February and Texas in the spring.

The closest approximation that Romney has to Gingrich's opening-day narrative is a pledge to sign an executive order allowing the states to opt out of the health care law. Instead, he stresses his credentials as a businessman while campaigning as the man who knows best how to create jobs.

Yet he and a third contender, former Pennsylvania Sen. Rick Santorum cast a suspicious eye on the political feats promised by Gingrich, who campaigns as the heir to the late President Ronald Reagan and who led Republicans to a House majority in 1994 for the first time in 40 years.

"Grandiosity has never been a problem with Newt Gingrich," Santorum said in a recent debate.

In television ads, Romney reminds voters of the ignominious end to Gingrich's tumultuous four-year speakership, after the House said he had violated ethics rules and he later lost the support among Republican lawmakers that was necessary to remain in power.

For boldness, Gingrich's Day One scenario trumps the Contract With America, the campaign manifesto that propelled Republicans to control over the House in 1994.

Then, Gingrich merely promised to hold votes on a 10-item conservative to-do list within the first 100 days of his speakership, without guaranteeing that any of the measures would clear Congress.

Like then, Gingrich talks of Republicans campaigning as a team, this time winning the White House as well as a majority in Congress. There was no presidential election in 1994.

The new Congress will convene on Jan. 3, 2013, he notes, while the presidential term begins at noon on Jan. 20.

"I will ask Congress to stay in session" in the meantime, he says, so legislation is ready for his signature on Inauguration Day that repeals the health care bill that stands as Obama's top domestic accomplishment, wipes out the so-called "Dodd-Frank" legislation that imposed new regulations on Wall Street and scraps a 2002 measure that toughened accounting rules.

Gingrich doesn't say so, but more than Republican majorities would be needed to accomplish this. Senate Democrats would surely filibuster to block the measures, raising questions about the fate of the repeal efforts.

Suggesting he has the day timed to the minute, Gingrich adds that "about two hours after the inaugural address" he will sign an executive order that eliminates all the czars Obama appointed.

Often, he promises to issue between 100 and 200 executive orders before the day ends, a large number that conveys big plans, but few specifics. Approving the construction of a pipeline between Canada and Texas is one, and in Tampa during the day, he said he would "repeal every Obama attack on religion."

In an aside meant to appeal to tea party sticklers for openness in government, the orders are to be posted online well in advance of the November election "so everyone in America will know what is coming."

In a gesture to participatory democracy, Gingrich invites suggestions on what orders can be issued.

With polls showing Republicans most want a candidate who can defeat Obama, Gingrich splices in a few barbs at the president, and some at Romney.

"With all due respect to Gov. Romney, there is an enormous difference of both how to move the nation and how to actually get things done in Washington," Gingrich said at The Villages. "This is a very hard complicated business. We've had three years of an amateur and we've understood it doesn't work very well.'