In brief
The Polymarket for the 2028 Republican presidential nominee shows Robert F. Kennedy Jr. leading with 49% probability, followed by Vice President J.D. Vance at 41.5%. Our analysis, based on recent political developments and donor signals, suggests Vance is the more likely nominee, despite RFK Jr.'s current market lead.
Introduction
As of July 13, 2026, the race for the 2028 Republican presidential nomination is taking shape, with Polymarket traders placing Robert F. Kennedy Jr. as the frontrunner at 49%. However, recent political developments—including President Trump's tacit endorsement of Vice President J.D. Vance and signals from major GOP donors—suggest the race is far from settled. This analysis examines the market data, key factors, and likely outcomes.
What to know
The Polymarket event "Republican Presidential Nominee 2028" resolves to "Yes" if the named individual wins and accepts the 2028 Republican nomination. The market closes on November 7, 2028, and has attracted over $672 million in volume, making it one of the most liquid political prediction markets.
According to Axios, GOP megadonor Ken Griffin stated at a private conference on July 8 that he would support Secretary of State Marco Rubio over Vice President JD Vance in a 2028 primary. This signals that establishment donors are actively considering alternatives to Vance.
Meanwhile, CNN reported on June 20 that potential candidates are cautious about openly positioning themselves for 2028, fearing backlash from President Trump. Vance, as the sitting vice president, is in a unique position but must avoid appearing too eager.
A Forbes analysis from June 19 noted that an Emerson College poll showed Vance leading Rubio 36% to 35% among likely GOP primary voters, with Vance's support dropping from 52% in February due to the Iran conflict.
President Trump has publicly backed Vance, with Sky News Australia reporting on June 16 that Trump said Vance would "do very well" in a potential 2028 bid.
RFK Jr.'s presence in the market is notable, but his history as a former Democrat and independent candidate raises questions about his ability to secure the Republican nomination. No major GOP figures have endorsed him.
The market numbers
| Outcome | Probability |
|---|---|
| Robert F. Kennedy Jr. | 49.0% |
| J.D. Vance | 41.5% |
| Marco Rubio | 27.9% |
| Tucker Carlson | 3.0% |
| Ron DeSantis | 2.5% |
| Donald Trump | 1.7% |
| Donald Trump Jr. | 1.3% |
| Vivek Ramaswamy | 1.3% |
| Glenn Youngkin | 1.1% |
| Ivanka Trump | 1.1% |
Data from Polymarket as of July 13, 2026. Total volume: $672,272,856. Total liquidity: $51,751,133.
The factors at play
- Trump's endorsement: President Trump's support for Vance is a significant asset, as the MAGA base largely follows his lead.
- Donor alignment: While Ken Griffin backs Rubio, other major donors may coalesce around Vance as the heir apparent.
- RFK Jr.'s viability: RFK Jr. has no established GOP donor network or institutional support, making his 49% market share appear inflated.
- Incumbency advantage: As vice president, Vance has a platform and visibility that other candidates lack.
- Foreign policy dynamics: The Iran conflict has affected Vance's polling, but it may also provide him with opportunities to demonstrate leadership.
- Timing of announcements: Candidates are waiting for Trump's signal before formally entering the race, which could shift dynamics.
Our prediction
According to our analysis, the most likely outcome is J.D. Vance. Polymarket currently assigns a probability of 41.5%, while our internal estimate is 55%. The difference stems from these factors: the market appears to overvalue RFK Jr., who lacks GOP institutional support and has not been embraced by party leaders or donors. Vance, as vice president, has Trump's backing, a clear path to the nomination, and is the natural heir to the MAGA movement. The market may also be discounting the likelihood that RFK Jr. either fails to secure ballot access or switches parties again before the primary.
Risks and uncertainties
- Trump's intervention: If Trump decides to run again or endorses a different candidate, the race could change dramatically.
- RFK Jr.'s appeal: If RFK Jr. successfully builds a coalition of disaffected voters and gains institutional support, he could become a serious contender.
- External events: A major crisis or scandal could reshuffle the field, as seen with the Iran war's impact on Vance's polling.
- Primary calendar: Early state results could create momentum for a dark horse candidate like Rubio or DeSantis.
- Legal challenges: RFK Jr.'s candidacy may face legal hurdles related to party affiliation and ballot access.
Conclusion
The 2028 Republican nomination race is fluid, with Polymarket traders favoring RFK Jr. but political realities pointing toward J.D. Vance. The next few months, including potential candidate announcements and the 2026 midterm elections, will provide clearer signals. For now, Vance remains the candidate to beat, despite the market's current pricing.
This content is for informational purposes only and does not constitute financial, political or investment advice, betting advice, or any operational recommendation.