There are no do-overs in presidential politics, but Texas Gov. Rick Perry sure is trying to have one.

Since touching down Thursday night in Iowa to begin a five-city tour of this crucial caucus state, Perry has been trotting out new lines that he probably wishes he had thought to use Monday night in Tampa at the Republican presidential debate.

On the debate stage, former Massachusetts governor Mitt Romney suggested that job growth in Texas had more to do with the state’s oil and gas boom than with Perry’s leadership, saying: “If you’re dealt four aces, that doesn’t make you necessarily a great poker player.”

This was Perry’s response: “Mitt, you were doing pretty good until you got to talking poker.”

Now, Perry has a sharper comeback that drives at the heart of the populist-vs.-elitist narrative his campaign has been trying to push in contrasting Perry’s modest upbringing with Romney’s more privileged life.

“I grew up in a house that didn’t have running water until I was about five years old. My mom and dad were both tenant farmers. For sure, I was not born with four aces in my hand. But, like many of you, I knew that the American dream was possible,” Perry told more than 100 Republicans at a Newton coffee shop Friday morning.

Perry uttered nearly the same line Thursday night in Jefferson, Iowa. The dinner crowd of about 250 Republican activists there laughed at his “four aces” reference, clearly remembering Romney’s line from the televised debate. Perry continued his riff:

“There have been some people saying, well, gosh, yeah, Texas has all that oil and gas. As a matter of fact, Governor Romney the other night said, well, it’s pretty easy to be governor if you’ve got four aces in your hand and you’re good at poker. There’s some folks back in Texas who are real offended by that. We work hard in Texas. We put good, hard, practical principles into play. And when you think about what it takes to guide that economy, that’s the 13th-largest economy in the world in the state of Texas, and we created that job machine.”

Perry also is sharpening his attack on Romney’s record, highlighting what he called Romney’s “legacy” of instituting “misguided health mandates” when he was governor of Massachusetts.

Citing a new report by the Beacon Hill Institute, a conservative think tank, that says Massachusetts has lost 18,000 jobs because of Romney’s health-care plan, Perry sought to link Romney’s plan with President Obama’s federal health-care overhaul.

“Governor Romney’s misguided health mandates slowed the income growth and cost Massachusetts 18,000 jobs,” Perry said in Jefferson, delivering a line he repeated here in Newton. “If it cost Massachusetts 18,000 jobs, think about what Obamacare is going to do to this country.”

The Romney campaign has said the Beacon Hill Institute’s study is “deeply flawed.”

“It is based on the assumption that Massachusetts health-care reform caused the rate of health-care cost increases to accelerate,” said Andrea Saul, a Romney campaign spokeswoman. “In fact, health-care cost increases have slowed since the passage of reform. This error therefore invalidates the study.”

But that hasn’t stopped Perry from hammering his message that Romney’s health-care record is akin to Obama’s.

“Government-mandated, government-run health care costs too much, it kills too many good jobs, it gets between you and your doctor,” he said. “It doesn’t make any difference whether it’s in Massachusetts or in Washington, D.C. It’s a bad concept. It doesn’t need to go forward. And I can tell you, as the president of the United States, I’m going to oppose any of those big-government health-care programs.”

Perry sharpened his critique on Romney’s health care law during a lunchtime speech Friday in Des Moines, likening it to socialism.

“The model for socialized medicine has been tried before,”Perry told a couple hundred members of the Iowa Credit Union Forum. “It didn’t work. It failed miserably — whether it was in Western Europe or in Massachusetts.”