Which Supreme Court justices will resign during Trump's term?

**Stage 1 — Blind analysis (ignore market prices):**

Clarence Thomas will be between ~76 and ~80 years old during Trump's term (Jan 20, 2025–Jan 20, 2029). Age alone materially raises the baseline chance of a justice choosing to retire at some point in that four-year window, because justices commonly time retirements around health, energy to continue, or political opportunity to place a like-minded successor on the bench. Two competing long-term forces push on Thomas's decision: *personal/institutional inertia* (Thomas has a long tenure, historically gives no public signals of imminent retirement, and has shown willingness to sit into advanced age) versus *ideological/strategic incentive* (a conservative justice has strong incentive to time a retirement for a Republican president, particularly one like Trump who would almost certainly nominate a conservative successor).

Key empirical priors: historically, justices often retire in their late 70s/early 80s; some conservative justices have resigned under friendly presidents to preserve the Court's ideological balance. Thomas's track record is to remain on the bench longer than many colleagues and to avoid public signaling. There are additional failure modes that could remove him from the Court without a voluntary resignation (sudden death or incapacitation) — those outcomes do not count as 'resignation' and therefore reduce the probability that the event (voluntary resignation during Trump's term) is realized.

Balancing these factors, I estimate Thomas has a materially better-than-even but still modest single-digit-to-mid tens percent chance of choosing to step down during 2025–2029. My independent (stage 1) probability is 42%.

**Why 42% concretely:** - Base-rate effect from age: a justice in the 76–80 range has a meaningful (roughly 30–50%) chance of leaving office in a given 4-year window from historical patterns, but that band is wide because individual habits vary. - Strategic/upside incentive: add ~10–15 percentage points because a conservative justice benefits from retiring under a Republican to secure an ideologically-aligned successor. - Thomas-specific reluctance: subtract ~5–10 points because of Thomas's demonstrated willingness to sit and his low public messaging about retirement. - Scandal/forced exit: treat as a low-probability tail; it slightly increases the chance of a voluntary resignation (if he steps down under pressure) but is not central to the baseline.

**Stage 2 — Market calibration (incorporate current market prices):**

The market price you supplied is Yes = 0.39 (39%), No = 0.61. My independent estimate of 42% is modestly higher than the current market. That gap (3 percentage points) is small; it could reflect several rational factors explaining why the market is a bit lower:

- Traders may be discounting the possibility of death or sudden incapacitation (which would produce a vacancy but not count as 'resignation') — the market effectively treats death/incapacitation as a 'No' for this contract, so uncertainty about mortality lowers the Yes price relative to the pure retirement incentive. - Liquidity/flow effects and risk aversion: given limited volume, larger players or hedgers may be pushing the price down to protect against tail risk (unexpected news that Thomas will stay) or because they believe the public presumes Thomas will not resign. - Information asymmetry: insiders or those close to the Court may be cautious; without explicit reporting from Thomas or the Court, traders may infer inertia is stronger than my priors assume. - Political risk premium: some traders might distrust a 'Trump window' as predictable — they may think Thomas would avoid retiring while a high-profile, polarizing president is in office, to avoid enabling chaotic confirmation fights if replacement politics becomes messy.

Given those plausible market-level considerations, the market price (39%) is sensible and close to my independent assessment. I view the market as slightly underpricing the resignation likelihood by ~3 percentage points; that difference is within normal model and market uncertainty. If new public signals about Thomas's health, travel, or explicit retirement mentions appear, the market should move quickly and could overshoot in either direction.

Bottom line: my independent probability (42%) is slightly above the market's 39%; the market likely reflects reasonable caution about mortality/inertia and limited on-chain information. I think an informed trade might be small-to-moderate on the belief that ideological timing and age push the chance a bit above current prices, but the edge is thin and news-sensitive.