JD Vance has always led Gavin Newsom in the odds. But this may change very soon. A few factors have completely decimated JD Vance's odds.

JD Vance was the default assumed pick for the Republican Party. He started the year with >50% odd for being selected. All others were at negligible odds. Now, Marco Rubio has improved to 20% odds, and JD Vance has shrunk to 38% odds. This has shrunk his lead from 47% to 16%.

The next factor, and really primary factor, is that ever since Trump started this war, the Republicans have taken an absolute nosedive in 2028 predictions. The democrat lead at the start of the year was only 6%, having 53% odds. Now the gap is 20% with Democrats having 60% odds of winning. The slope of this rise really took off starting March 17th, and has only gotten steeper. Despite the already significant movement, the immediate slope of the curve, as it is right now, has never been steeper than it is right now (at the current time of writing).

The last factor is that no one has stood up as a possible contender to Newsom for the Democrat nominee still. AOC remains the second position in the nomination race, and has been since the beginning. But she has fallen at a steady clip. From 16% odds at the start of our data, to 12% at the start of the year, to 8% as of now.

Now Gavin's odds alone are not that high to get the nomination, only having 24%. This tracks with the historic pattern of the DNC. Typically they will run one favorite for a long time, and then pick a winner internally last minute. Then do whatever it takes to get them over the finish despite constituent preferences differing. This gives them an advantage of having a clean candidate that has avoided a long mud fight go into the general election. So we really don't know who the DNC will run. We won't know for a long time. But despite that, the fact that it is probably not Newsom, still puts Newsom now tied with JD Vance due to the absolute slide that the Republican party has taken in the last month.

Reference markets:
https://polymarket.com/event/presidential-election-winner-2028
https://polymarket.com/event/republican-presidential-nominee-2028
https://polymarket.com/event/which-party-wins-2028-us-presidential-election
https://polymarket.com/event/democratic-presidential-nominee-2028