WASHINGTON — Marco Rubio is riding a new wave of momentum as he prepares for Tuesday’s GOP presidential debate, with rising poll numbers and fresh endorsements from fellow senators. But he also faces increased scrutiny for his use of a Republican Party-issued charge card during his time as a Florida state legislator.

The debate in Milwaukee offers Rubio, now solidly in third place behind front-runners Donald Trump and Ben Carson, another chance to showcase the debating skills that have helped propel him upward in the polls.

His rivals will work to sideline those skills by focusing attention on the personal goods and services the Florida senator bought between 2005 and 2008 with an American Express card issued to him by the Republican Party of Florida.

Trump has aggressively gone after Rubio on the issue, a possible preview of his strategy at Tuesday’s Fox Business Network debate. Last week, the billionaire businessman told reporters that Rubio “is a disaster with his credit cards.”

Rubio has said he reimbursed the party for any personal expenses he charged to the card. He responded to Trump two days later, saying it's “ironic that the only person running for president that’s ever declared bankruptcy — four times in the last 25 years — is attacking anyone on finances.”

Over the weekend, Rubio disclosed 22 months (January 2005-October 2006) of previously unreleased statements linked to the American Express card.

The statements show Rubio bought 484 items for a total $64,778, including eight personal charges totaling $7,244. Personal expenses included flooring, a Las Vegas hotel room and a children’s sports activity center; all of which his campaign said he repaid.

Rubio has acknowledged “it was a mistake” to use the charge card for personal use even though it involved no taxpayer funds and was fully reimbursed.

Pundits expect the issue to come up at the debate but don’t see it resonating much on the campaign trail. They say criticism will be blunted by Rubio's overall likability and his feel-good personal history as the son of an immigrant bartender and maid who rose to become a serious presidential contender.

Misusing a charge card isn’t unusual for someone unaccustomed to handling a lot of money and could ultimately benefit Rubio politically, said Patrick Murray, director of the Monmouth University Polling Institute in New Jersey.

“It actually confirms for a lot of voters that, ‘This guy understands us (and), because he’s one of us, I can imagine myself being in that position. I’m going to cut him some slack,’” Murray said.

The institute released a poll Monday showing Rubio in third place at 11% among likely Republican primary voters in South Carolina. When the four candidates with outsider appeal — Trump, Carson, former Hewlett-Packard CEO Carly Fiorina and Sen. Ted Cruz of Texas — aren't included in the survey, Rubio does even better, dominating the field of establishment Republican candidates with 32%.

Endorsements have added to Rubio's momentum.

Last week alone, he was endorsed by three Republican senators: Cory Gardner of Colorado, Steve Daines of Montana and James Risch of Idaho.

“I think Marco Rubio represents the best opportunity for the future,” said Gardner, considered a rising Republican star in a key swing state.

Another stellar performance at Tuesday's debate will only send Rubio's ratings higher, which is why his rivals likely will take aim at his credit card history, said Aubrey Jewett, an associate political science professor at the University of Central Florida.

“Good news and bad news,” Jewett said. “You’re doing better, but you re going to get more scrutiny. I don’t think we’ve heard the last of it.”