Washington DC - Donald Trump's potential vice president picks have been playing defense for the Republican candidate, but they can't seem to agree on whether he'll seek vengeance against his political rivals if re-elected.

On Sunday, Florida Senator Marco Rubio played down any fears of retribution on CNN, arguing that as president, Trump didn't "go after" rivals like Joe Biden and Barack Obama.

"He's already said that he wouldn't do that," Rubio said. "He'll be too busy undoing all the damage of this disastrous presidency."

That same day, though, Ohio Senator JD Vance went on NBC News to say it would be "totally reasonable" for Trump to launch investigations into Joe Biden if he wins.

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"The Biden administration has done far worse," Vance argued, without giving any evidence. "So, if you think that what Donald Trump is proposing is a threat to democracy, isn't what Biden has already done a massive threat to our system of law and government?"

Rubio and Vance are considered top contenders to be Trump's possible running mate.

During his 2016 presidential campaign, Trump popularized the phrase "Lock her up!" in reference to his Democratic challenger at the time, Hillary Clinton.

Trump has faced a number of legal battles and scandals, all of which he has aggressively blamed, without evidence, on his political rivals.

This rhetoric has sparked concerns that, if re-elected, he would use his power in office to "get back" at those he claims did him wrong.

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Despite Rubio's claims, the former president has flirted with the idea on several occasions, strategically choosing to do so on social media and at his rallies, which serve as his direct lines to his MAGA base.

Last year, during a rally in Bedminster, New Jersey, Trump laid out his plan to appoint a special prosecutor to investigate Biden, and called for supporters to "haul out the guillotine" in a campaign email dripping with resentment at critics.

But in more formal interview settings, Trump has instead repeatedly insisted that his "revenge" will come in the form of him winning a second term.

Trump is expected to announce his VP at the upcoming Republican National Convention on July 15.