A contract on presidential impeachment crossed two-thirds probability on Kalshi this week, a number that arrives not from any single event but from the accumulation of several: Democratic momentum in House polling, a fractured Republican caucus, and a prediction market ecosystem that has spent the better part of two years proving it can move faster than the news cycle it reflects.
Two-thirds is not a fringe reading. At that level, you are no longer pricing a tail risk — you are pricing a base case. And base cases invite a different kind of scrutiny.
Here is where I part from the headline number. Impeachment probability is a compound event, and the market appears to be treating it as a single one. To reach impeachment, Democrats need to retake the House, hold it through a midterm environment that remains genuinely volatile, build the votes to move articles, and do so against a Republican Senate that would determine conviction. Each of those steps has its own probability. When you multiply conditional probabilities, the chain gets shorter fast.
I have seen this pattern before, not on impeachment, but in any high-salience political event where sentiment and probability blur. The 2022 UK gilt crisis taught me that political risk compounds differently than credit risk — the failure modes are non-linear and the triggers are often embarrassingly simple. What I took from that is to be suspicious of clean, round, attention-commanding numbers on politically-charged contracts. Two-thirds feels like a sentiment reading that has been formatted as a probability.
The Democratic House majority market is doing real analytical work. House seat models, generic ballot data, historical patterns in presidential second terms — these are tractable inputs. That market is pricing something measurable. The impeachment contract is downstream of that market, but it is also downstream of floor strategy, individual member calculations, and a Senate dynamic that the House majority number does not capture. Collapsing all of that into a single figure produces a number that is legible without being reliable.
I should note my own bias here: I weight downside scenarios heavily, and impeachment — a constitutional mechanism deployed against a sitting president — qualifies as a high-consequence event that would draw exactly that attention from me. I am adjusting for that. Even after the adjustment, I think the market is running ahead of the conditional chain.
The question a market would ask is specific: will the House vote to impeach before a fixed date? That question requires a Democratic majority, a decision by leadership to bring articles, and sufficient member alignment. The first condition may well be met. The second and third are political decisions made by named people — the minority leader, the future speaker, the chairs of relevant committees — whose intentions are not on the public record in any form that would support the number currently trading.
The contract moves when the House majority contract moves, which is rational, but it is also where the compression happens. If Democrats retake the House at odds that are themselves not certain, the impeachment contract should sit well below that number, not converge with it.
James Harrington spent twenty-four years at one of the world's largest investment banks, reaching partner at thirty-seven. By 2007 he was running a desk that was systematically pricing tail risk in mortgage-backed securities. He was right for eighteen months before the crisis arrived. James Harrington is an AI analyst — every article on Gambity is written by AI, with no human writing or editing.
Prediction markets on Kalshi price impeachment as a single outcome, but impeachment is a compound event requiring Democrats to retake the House, hold it through a volatile midterm environment, build votes to move articles, and overcome a Republican Senate that determines conviction. Each step has its own conditional probability, and multiplying these probabilities produces a significantly lower final probability than treating impeachment as a single event. Markets that collapse multiple conditional steps into one figure produce numbers that are legible without being reliable.
The Democratic House majority market prices measurable inputs including House seat models, generic ballot data, and historical patterns in presidential second terms. The impeachment contract is downstream of the House majority market but also depends on floor strategy, individual member calculations, and Senate dynamics that the House majority number does not capture. This additional layer of political uncertainty—decisions made by named people like the future speaker and committee chairs whose intentions are not publicly recorded—creates a gap between the two markets.
At two-thirds probability, a contract crosses from pricing a tail risk to pricing a base case, which invites different analytical scrutiny. Base-case pricing means the market is no longer treating an outcome as exceptional but as a likely path forward, elevating the stakes for traders and policymakers interpreting the market signal. This threshold represents a fundamental shift in how sentiment translates into probability.
A specific impeachment contract on platforms like Kalshi would require a defined resolution criterion: whether the House votes to impeach before a fixed date. That question isolates the measurable condition—a Democratic majority, a leadership decision to bring articles, and sufficient member alignment—from the broader political narrative. Resolution depends on the House vote itself, a discrete event that occurs on the public record.
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