In an interview with Fox News Channel’s Bret Baier Monday night, Sen. Marco Rubio (R-Fla.) addressed some parts of his political history that have dogged him, including his use of a Florida Republican Party credit card for personal purchases as well as his relationship with embattled Rep. David Rivera (R-Fla.)

The interview comes as Rubio, a freshman who served for nine years in the Florida state House before winning election go the Senate in 2010, is increasingly being floated as a potential VP choice for former Massachusetts governor Mitt Romney, the presumptive Republican presidential nominee.

On his use of the Florida GOP credit card, Rubio acknowledged, “I shouldn’t have done it that way. It was lesson learned.”

But he also argued that “it’s important people understand I did not bill personal expenses to the Republican Party of Florida.”

“At the end of every month, we would get those statements,” he told Baier. “We would see what was on there that was party-related, and the party would pay that. If it wasn’t party-related, I would pay that directly to American Express.”

He continued: “Now, obviously, in hindsight, it looks bad, right? I mean, why are you using a party credit card at all? Well, some of these expenses were because a travel agent had the number, you know, the credit card number, and they billed it to that card instead of the other card. Sometimes, it was just a mistake, you know, literally just reached for the wrong card.”

The Miami Herald and the Tampa Bay Times (then known as the St. Petersburg Times) reported during Rubio’s Senate bid that the Florida Republican had billed the state party for more than $100,000 during the two years he served as state House speaker:

The charges included repairs to the family minivan, grocery bills, plane tickets for his wife and purchases from retailers ranging from a wine store near his home to Apple’s online store. Rubio also charged the party for dozens of meals during the annual lawmaking session in Tallahassee, even though he received taxpayer subsidies for his meals.

Rubio said the billings all related to party business — the minivan, for example, was damaged by a valet at a political function — and that he repaid the party for about $16,000 in personal expenses.

In the Fox News Channel interview, Rubio also addressed his relationship with Rivera:

RUBIO: He’s a friend. I mean, he’s a friend I’ve known on a personal level even before I was elected or he was elected to office. So look, I know he’s going through a tough time. And we’ve all read the press reports and none of us like to see that about anybody, much less a friend. And he’s going to have to deal with those issues.

BAIER (voice-over): Those issues, in case you haven’t seen the press reports, are allegations that Miami Republican congressman David Rivera misused various offices and campaigns for personal gain. He’s reportedly been under investigation by at least five different law enforcement agencies for a range of violations, including payments of more than a half million dollars from gambling operations after legislation passed in the statehouse that he lobbied for, money authorities say he received through a company set up by his mother and godmother.

RUBIO: I guess it’s because I’m new to Washington, but I’ve never felt it -- I mean, maybe it’s acceptable here -- it isn’t to me -- to turn your back on friends when they’re going through a difficult time, no matter, you know, what they may have done or not done, you know? And so in his case, he’s a friend and I’m going to give him the benefit of the doubt.

BAIER (on camera): And you’re raising money for him.

RUBIO: Yes. You know, again...

BAIER: You’re holding a fund-raiser for him.

RUBIO: Well, he’s a friend. He’s -- and he’s asked me to attend a fund-raiser. He’s accountable to the people of his district who elect -- who elected him and are going to have to reelect him.

BAIER (voice-over): Rubio is hosting a fund-raiser for Rivera in May. Adding to the media questions, Rivera and Rubio bought a house together in Tallahassee during their time in the statehouse, a house the bank was moving to foreclose.

RUBIO: There was a disagreement with the bank about how much the monthly payments were. And it all got confusing. The bank turned it over to a -- one of these lawfirm in Florida that specialized in quick foreclosure proceedings. And before we could figure it all out with them, they filed this paperwork. So we quickly addressed it, and we’ve never had a problem since.

BAIER (on camera): You were not not making payments.

RUBIO: Yes, there was a disagreement over the amount per month. And so to them, that’s not -- those are not complete payments. And -- and -- so there were all kinds of other things that happened as a result of that. But that all got worked out as soon as we found out about it. Certainly, as soon as I found out about it, we addressed it and we moved on with it. Now, I’ve been handling that personally.

BAIER (voice-over): Whether those issues are enough to keep Rubio off a Romney ticket will be up to the vetting.

The full transcript of the interview is available here.