Is Marco Rubio The New Heir Apparent To Trump?

For months, the conventional wisdom inside Republican circles has been settled and simple: JD Vance is next. The vice president has led 2028 Republican presidential nomination polling by a country mile, averaging nearly 45.5 points in the RealClearPolitics aggregate — more than 30 points ahead of Donald Trump Jr. at 14.8% and Marco Rubio at 14%.

And yet, something shifted this week. One press briefing, and the betting markets started hedging.

Rubio stepped in as White House press secretary on Tuesday, covering for Karoline Leavitt while she’s on maternity leave, and delivered what even the skeptics had to acknowledge was a polished, commanding performance. He defended the war in Iran before a press corps not exactly known for its generosity toward administration officials — and walked away with his standing improved. The room, by most accounts, was notably less adversarial than it tends to be when Leavitt or Trump takes the podium. Rubio was fluid and measured, giving the journalists little to sharpen their teeth on. 

Washington noticed, and Kalshi, one of the leading prediction markets, noticed too. 

By Tuesday, Rubio had leapfrogged Vance to become the overall favorite to win the 2028 presidential election, coming in at 18% to Vance's 17%. Gov. Gavin Newsom sits just behind at 16% - a reminder that the Democrats haven't entirely vacated the field in the markets' eyes.

For Rubio, the jump is particularly striking given that he was sitting in the single digits on Kalshi earlier this year. 

Polymarket still has Vance in front overall - 19.6% to Newsom's 16.7% and Rubio's 15%. 

On the GOP nomination question specifically, Vance retains a meaningful edge on Polymarket (though Rubio's odds are rising). Primary voters and general-election bettors, it turns out, are pricing these things very differently.

None of this, of course, happens in a vacuum. Trump himself has been notably careful — or deliberately noncommittal — about who carries the MAGA torch after January 2029.

Weeks into his second term, Trump sat down with Fox News's Bret Baier and declined to designate Vance as his heir apparent, saying simply that it was too early for such an endorsement. For a president who has never been shy about anointing winners and losers, that hesitation was conspicuous to say the least. He left the door ajar, and markets being markets, traders are now watching to see who walks through it.

Trump says he does not view JD Vance as his successor and declines to endorse him in 2028, saying it’s too early and that there are “lot of very capable people.”pic.twitter.com/xRtnX1DgZ2

— bryan metzger (@metzgov) February 10, 2025

Vance remains the favorite by most conventional metrics. His polling advantage is enormous, and he’s been the heir apparent since joining the Trump ticket in 2024. 

But Rubio's trajectory is definitely worth watching to see if his stock goes higher or merely plateaus. His rise from the low single digits to within striking distance of Vance on Kalshi over just a few months could be a one-off or the opening act of a longer repositioning.

For now, Vance’s commanding polling lead offers the most grounded picture of where Republican voters actually stand.

But, prediction markets have a knack for capturing things polls don’t. And it will likely take some time to determine if Rubio’s rise will stick.