At a Boca Raton, Fla., event ostensibly touting the Buffett Rule on Tuesday, President Barack Obama appeared to be putting the finishing touches on his stump speech as his re-election campaign gears up to take on Mitt Romney in the fall.

Minutes after Rick Santorum dropped out of the GOP race, Obama jokingly alluded to his rivals as “people who are running for a certain office right now who shall not be named” and tore into the Republican agenda as pouring more tax breaks onto the wealthy while draining investments in the middle class.

“I believe the free market is the greatest force for economic progress in human history,” Obama said, but he made a pitch for government to step in as well — for schools, the military, Medicare, Medicaid, Social Security, unemployment insurance and public investments.

“We can’t build a highway for ourselves,” Obama said. “We’ve got to get our neighbors and our friends to say, ‘Let’s go build a road.’”

Obama said the tilting of economic growth to the rich “drags our entire economy down.”

“In this country, prosperity has never trickled down from the wealthy few,” he said. “Prosperity has always come from the bottom up, from a strong and growing middle class.”

Obama suggested that Republicans love their country but don’t seem to understand how it got to where it is.

“We keep on having the same argument with folks who don’t seem to understand how it is that America got built,” Obama said.

“These folks, they keep telling us that if we just weaken regulations that keep our air or our water clean, or protect our consumers, if we would just convert these investments that we’re making to our government in education, in research, in health care, if we just turn those into tax cuts, especially for the wealthy, then somehow the economy’s going to grow stronger,” he added.

“That’s the theory. And here’s the news. We tried this for eight years before I took office. We tried it.”

Obama appeared to be giving a preview of his attack line against Romney and the GOP this fall.

“Instead of saying, ‘You know what, what we did really didn’t work and we almost had a second Great Depression, and maybe we should try something different,’ they have doubled down,” he said.

“They’ve proposed a budget that showers the wealthiest Americans with even more tax cuts and then pays for these tax cuts by gutting investments in education, in medical research, in clean energy, in health care.”

Obama said Republican proposals for an additional $4 trillion in tax cuts won’t come “from some magic tree somewhere,” but the GOP won’t say who will pay more or who will lose benefits.

He added that passing the Buffett Rule “makes it affordable for us to be able to say for those people who make under $250,000 a year, like 98 percent of American families do, then your taxes don’t go up. And we can still make those investments in things like student loans and college and science and all — infrastructure and all the things that make this country great.”

Obama’s boast appears to overstate what the Buffett Rule actually does. It raises about $47 billion over the next decade — hardly a princely sum and nothing approaching the $3 trillion-plus cost of extending tax cuts for the middle class. In an era of trillion-dollar deficits, it’s a drop in the bucket.

Republicans ripped Obama and the Buffett Rule before the president spoke, arguing he was trying to distract from his record with class warfare.

“This has nothing to do with sound economic policy to get our economy moving again and everything to do with politics,” Senate Finance ranking member Orrin Hatch said. The Utah Republican dismissed the revenue raised by the new 30 percent minimum millionaire tax as “a spit in the ocean.”

Still, the president urged his audience to contact Congress. “Remind them who they work for,” he said.

Obama ended on a rhetorical flourish, his voice rising to cheers. “Here in America we look out for one another. … Here in America we can seize any moment. We can make this century another great American century.”