NEW YORK (Fortune) — Now the Democrats aren’t the only ones who can try to capitalize on the negative buzz growing around Alaska Gov. Sarah Palin, the prospective Republican VP candidate.

Intrade, an online prediction market based in Dublin, created a contract Tuesday morning on the likelihood that John McCain will drop Palin

After opening at a probability of just 3%, the odds on Palin being cut from the ticket climbed to 18% around 9 a.m. and have since settled at around 12%.

Placing a Palin withdrawal at even 12% seems bullish; no presidential candidate has withdrawn his VP selection since Thomas Eagleton left Democratic candidate George McGovern’s ticket in 1972.

Intrade has demonstrated some success in predicting political choices (forecasting the selection of Biden), but also volatility: Palin’s chances of landing the nomination vacillated wildly in the hours before McCain announced the pick in the late afternoon.

Intrade monitors its traders’ demographics, but it’s too early to tell who’s betting on a Palin pullout. Some of the naysayers could be Republicans: Rigetti says that, unlike polls, the election markets don’t always represent political beliefs. “People have a real money incentive,” he says. “They’re betting with their head and not their heart.”