Vice President JD Vance and Secretary of State Marco Rubio have both dropped in 2028 Republican nomination odds on major prediction markets as traders reassess the field before the midterms.

On Polymarket, Vance’s share fell from roughly 53 percent on September 3 to 43.8 percent by Tuesday, while Rubio dropped from 27.8 percent on August 3 to 15.1 percent. Kalshi showed a similar pattern: Vance moved from 45.8 percent on September 3 to 43 percent, and Rubio from 29.5 percent on August 3 to 18 percent.

Newsweek reviewed the two platforms and found both men still lead the Republican field, yet the recent drift has drawn fresh attention to succession talk, family considerations, and the political weight of the next midterms.

Polymarket’s Republican presidential nominee market has seen almost $714 million in cumulative trading. Kalshi, a U.S.-regulated prediction market, has tallied nearly $70 million. Those volumes make the price moves hard to dismiss as a blip, even if they are not the same thing as a poll.

Weekend remarks and a four-point weekly dip

Over the weekend, Vance said there was “of course” a chance he would not seek the presidency. He pointed to four young children and his wife’s dislike of politics. Newsweek emailed the White House and the State Department on Tuesday seeking comment from Vance and Rubio.

Koleman Strumpf, a Wake Forest University economics professor who studies prediction markets, cautioned against reading the move as a collapse. He told Newsweek that Vance had fallen by roughly four points over the past week, and that only some of that shift followed the remarks.

Strumpf said some of the money flowed toward longer-shot names, and that the lack of one clear winner suggested traders did not treat the comments as decisive.

"I think the main message is that people are not reading much into the announcement,"

Strumpf said. He still ranks markets highly as a forecasting tool, arguing that constant trading gives them an edge over static snapshots.

Earlier coverage has tracked how Trump has signaled preference for Vance in succession talk, which makes any market wobble for the vice president notable even when the underlying lead remains intact.

Rubio’s longer slide and a crowded undercard

Rubio’s decline stretches further back. From early August to Tuesday, his Polymarket share fell more than 12 points, and his Kalshi figure dropped more than 11 points. Florida Gov. Ron DeSantis and commentator Tucker Carlson remain in the low single digits as alternate names on the boards.

The market picture for Rubio has grown more awkward on the Democratic side of the same platforms. The Washington Examiner reported that Rep. Alexandria Ocasio-Cortez has overtaken Rubio in 2028 presidential odds on Polymarket, a crossover comparison that underlines how far Rubio’s price has drifted even as both parties keep public focus on 2026.

Political communications strategist Mike Fahey told Newsweek the two men are different political personalities who remain tied to the same administration. If confidence in that administration slips, he said, both can take hits at once.

"Vance and Rubio are two different political personalities, but they’re still tied to the same administration,"

Fahey said, adding that deteriorating confidence can punish them together.

Readers following the succession fight will recall reporting that Trump had settled on Vance over Rubio in preferred-successor talk, which helps explain why Rubio’s market price may be more exposed when traders reprice the wider field.

Midterms loom larger than any single weekend quote

Several political scientists framed the odds shift less as a verdict on Vance’s family comments and more as traders looking ahead to November 3 midterms and the final two years of the Trump administration.

Costas Panagopoulos, a distinguished professor of political science at Northeastern University, told Newsweek by phone that Republicans tied closely to the administration may stay cautious for now.

"Any Republican looking at their prospects for 2028 right now may be cautious, especially anyone so closely linked to Trump and his administration,"

Panagopoulos said. He added that a rough midterm could put blame on the president and, by extension, on high-profile figures around him, while also noting that two years remain and outcomes are still open.

Thad Kousser, a University of California San Diego political science professor, said association with Trump has been the strongest force in GOP primaries for a decade. The open question, he argued, is whether 2026 results change that math heading into 2028.

Separate polling snapshots have not always matched the markets. One recent survey found Rubio outperforming Vance against top Democrats in hypothetical general-election matchups, a reminder that trader prices and voter surveys can diverge for long stretches.

Daniel Schatz, a political scientist and former Harvard visiting scholar, told Newsweek a bad midterm could turn proximity to power from an asset into a liability and that the contest could open up. He also noted traders can lose confidence in the two favorites before they settle on a replacement.

"Traders can lose confidence in the two favorites before agreeing on an alternative,"

Schatz said.

Markets are not polls, and the field is still early

Keith Gaddie, who holds the Hoffman chair of the American Ideal at Texas Christian University, warned against treating the boards like public opinion surveys.

"These are not polls,"

Gaddie said. “It is dangerous to view them as a proxy for public opinion.” He suggested traders may be hedging, and that Vance’s remarks could mix expectations management with a desire to keep options open.

Strumpf, for his part, still prefers markets when forced to choose a single forecast source, pointing to second-by-second trading and the way contract values can multiply before expiration. Panagopoulos argued Republicans remain “the only game in town” for now on the right, but said the party may need post-2026 soul-searching about its post-Trump shape if the midterms deliver a sharp verdict.

Vance has also publicly left room on timing and endorsements, including comments that an early Trump endorsement for 2028 is not locked in, which fits a pattern of keeping the calendar flexible while the administration’s record is still being written.

Rubio continues to operate as secretary of state on foreign-policy fights that keep him in the national frame, from alliances to war-support decisions, even as nomination traders mark him down from his summer highs.

For now the boards still put Vance first and Rubio ahead of the low-single-digit alternatives. The recent price action does not crown a new favorite. It shows traders shaving probability from the two best-known administration names while they wait on midterm results, governing outcomes, and clearer signals about who runs.

Prediction markets reward cold arithmetic over cable chatter, and Republicans who want 2028 clarity will get a louder answer from voters in 2026 than from any weekend quote.