(CNN) -- As President Barack Obama was about to deliver his State of the Union address on Tuesday, his prospective Republican challengers were busy laying the groundwork for their efforts to challenge the incumbent.
Three of the four Republican candidates held events in Florida on Tuesday, a week before the state's crucial primary.
While focusing criticism on Obama to try to dim the president's limelight, the candidates also managed to get in some shots at each other in the aftermath of a spirited debate Monday night.
"The president will do what he does best. He'll give a nice speech, a lot of memorable phrases in it, but he won't give you the hard numbers like 9.9% unemployment here in Florida," former Massachusetts Gov. Mitt Romney predicted at a campaign event in Tampa. "... Instead, tonight President Obama will make the opening argument for his campaign against a do-nothing Congress."
Romney spoke at an abandoned factory, in front of an American flag and a banner that read, "Obama isn't working." He later spoke in front of a foreclosed Florida home to emphasize the economic hardships facing many Americans.
"Today, too many factory floors are silent, warehouses are deserted, corporate offices are empty and real estate endeavors are abandoned," Romney said. "Floridians are struggling to find a job, keep a home and raise a family. This is the real state of our union, but you won't hear stories like those at President Obama's address tonight. The unemployed don't get tickets to sit next to the first lady."
Former House Speaker Newt Gingrich, whose poll numbers have surged in the wake of his primary victory on Saturday in South Carolina, said at an event in St. Petersburg that change must occur at the White House, in Congress and in the bureaucracy of Washington.
"It's bigger than Obama," Gingrich said. "While he's the start, there's much more to getting this country back on track than Obama."
Later, in Sarasota, Gingrich said that, if elected president, his first acts would be to sign executive orders undoing policies of the Obama administration.
"By the time President Obama lands in Chicago, we will have dismantled about 40% of his administration," Gingrich said to cheers.
His strongest barbs, however, were aimed at Romney, the early front-runner in Florida who has seen Gingrich close the gap in recent days in polls. Romney leveled attacks against Gingrich during Monday's debate, the first of two this week before Floridians vote in their January 31 primary.
A different candidate has won each of the first three nominating contests so far, but Romney's strong organization and war chest are considered an advantage as the primary process proceeds.
"Look, I need your help between now and next Tuesday," Gingrich told his supporters, referring to the primary date. "The fact is, Gov. Romney will have vastly more money than I will, but we will have many more people than he will. This is exactly what happened in South Carolina, and people power beats money power every time."
Still, Gingrich's campaign finances were improving: A super PAC backing Gingrich, Winning Our Future, bought $6 million in ads in Florida, a spokesman for the group, Rick Tyler, told CNN.
The buy came one day after major Republican donor Miriam Adelson contributed $5 million to the organization.
Also Tuesday, Romney's 2010 tax return and an estimate of his tax liability for 2011 underwent scrutiny.
The documents reveal he made $42.7 million over the past two years and paid $6.2 million in taxes, with an effective federal income tax rate of just under 14%.
At an event in Stuart, Florida, former Pennsylvania Sen. Rick Santorum contrasted his finances with those of his rivals at an event in Stuart, Florida.
"When you see my tax return, you will note that I do not have the riches of others in this race," said Santorum, who is vying with Gingrich to become the favored conservative candidate of the primary campaign against the more moderate Romney.
Santorum preemptively criticized Obama's speech by blaming the president for increasing the size of the government, increasing deficits and debt, and seeing the U.S. credit rating downgraded on his watch.
Santorum, citing Obama's legislation on health care and Wall Street, called him "the worst president this country has ever seen."
"You are going to hear a bunch of flowery rhetoric and all this stuff about all the things he has done," Santorum said. "But what he has done -- he has grown the tax burden on the American public through Obamacare, through Dodd-Frank and through other bills."
Santorum also leveled criticism at Romney and Gingrich in a fundraising letter that repeated his debate attack Monday night that accused both of his rival candidates of having betrayed conservative principles on major issues such as health care and global warming.
"On the big issues, Newt Gingrich and Mitt Romney are not all that different from Obama," the letter said.
In Punta Gorda, Santorum dismissed reports of growing income inequality in the nation.
"Income inequality is going to happen, some people are going to make more, some people are going to make less," Santorum said. "People ask me, 'What do you think about Mitt Romney, you know, making a gazillion dollars last year?' Good for him, that's what I say, good for him. I wish I'd made some gazillion dollars last year. I'd be in a little better shape financing my own campaign like he's done. Good for him, that's OK. The problem is, and this is something Republicans and conservatives need to be concerned about, is the ability of people to rise. The ability of people to climb the ladder."
In an interview with CNN, Gingrich cited his appearance in an advertisement about climate change with a Democratic former speaker. "The dumbest thing I've done in the last four years was sit on a couch with Nancy Pelosi," he said.
Pelosi pushed back sharply. "I think he's done plenty of dumb things and there's stiff competition for what is the dumbest thing he's done, of course, including his violations of the ethics rules of the House of Representatives," she told CNN.
Pelosi needed no polls in making her prediction about the outcome of the race. "He's not going to be president of the United States," she said. "That's not going to happen."
Texas Rep. Ron Paul has decided not to spend money in Florida because of his poor prospects in the winner-take-all primary. Instead, he is focusing on upcoming caucuses in Nevada, Colorado and Minnesota in a bid to win more delegates so he can wield influence at the Republican convention in August.
Florida is a key battleground and offers a different campaign landscape.
The number of Florida Republican voters exceeds the combined total in the previous three states, requiring a larger campaign organization and more money for advertising. Romney got a head start in the state over his rivals and is expected to receive a boost from the early voting that the state permits.
According to the state, at least 53,000 ballots had been cast in early voting that started on Saturday. Of the 475,000 people who requested and were sent absentee ballots, 180,000 had been filled out and sent back by last Wednesday.
Those absentee votes came in before Gingrich rose in the polls and won South Carolina's primary by a double-digit margin. In 2008, nearly 1.95 million people voted in Florida's GOP primary.
According to Gallup's daily tracking poll, Gingrich is in a statistical tie with Romney nationally among registered Republicans.
The national poll showed Romney at 29% and Gingrich at 28%. After the New Hampshire primary this month, Romney was at 37% and Gingrich at 14% in the same poll.
Monday's poll results showed Paul at 13% and Santorum at 11%. The sampling error was plus-or-minus 3 points.
CNN's Jim Acosta, Rachel Streitfeld, Tom Cohen and Adam Aigner-Treworgy contributed to this report.