REPLAY CASE · POLITICS · RESOLVED JULY 21, 2024

Fifteen Days: Biden Drops Out, Harris Becomes the Nominee

Between June 27 and July 21, 2024, the Polymarket 'Biden withdraws before convention' market climbed from 14% to 96%. The catalyst was a single debate performance on the 27th — but the market did not move in a straight line. It surged the night of the debate, then drifted back as the White House denied, drifted up again on private donor pushback, drifted back on a Stephanopoulos interview that was supposed to settle it, and finally went vertical on July 21 when Biden's letter posted to X at 1:46 PM ET. This case is about reading a slow-burn information cascade: every news cycle either confirmed the trajectory or briefly looked like it broke. The skill is staying with the trend when each individual data point feels like noise.

WHAT YOU'LL LEARN

"Slow-burn political crises move on cumulative evidence, not single events. The market is reading the whole letter, not waiting for the punctuation."

· You'll watch the market process information in real time from June 27, 2024 through July 21, 2024
· You'll trade with $100 in simulated USDC. No real funds move at any point.
· After the replay ends, you'll see a debrief: what your decisions would have returned, where you anticipated the move, where you chased.

Start Replay →← Back to library ↯ Did you predict this at the time?↯ What was the news saying at the time?INTERMEDIATE · ~90MIN AT 8×

CONTEXT

What was knowable at the time.

What was knowable

· Biden had been holding 38-42% approval through Q2, well below Trump's head-to-head number.
· The June 27 debate format (no audience, no fact-check, rigid timing) was designed to favor a disciplined performer.
· His age was the persistent question — 81, the oldest sitting president.
· Polymarket's "Biden out before convention" market had been trading 11-15% through June.

What broke that night

· Eight minutes in, Biden lost his train of thought mid-answer on Medicare.
· The market jumped 14% → 31% during the debate hour.
· Within 48 hours, the NYT editorial board and other major papers had called for him to step aside.
· The White House counter-narrative held for ~10 days, then collapsed when Pelosi went on Morning Joe.

ARCHIVE · 7 EVENTS

Headlines you'll see during the replay.

Each headline appears in the news feed at its original timestamp as the replay progresses. Major events get a violet left-border. This is the primary source archive: real headlines from real moments.

Jun 27, 10:00 PM UTC · CNN

Presidential debate begins

Jun 27, 10:08 PM UTC · Live debate

Biden loses train of thought mid-answer on Medicare

The moment the market started moving. Polymarket: 14% → 31% during the debate hour.

Jun 29, 06:00 PM UTC · New York Times

NYT editorial board: Biden should step aside

First major editorial call. Market: 38%.

Jul 05, 10:00 PM UTC · ABC News

Biden Stephanopoulos interview airs — defiant, denies stepping aside

Brief retracement. Market: 38% → 28% over 24 hours.

Jul 10, 04:00 PM UTC · MSNBC

Pelosi on Morning Joe: 'It's up to the president'

The interpretive language was unmistakable. Market: 32% → 54% in three hours.

Jul 17, 08:00 PM UTC · Politico

Biden tests positive for COVID, cancels rally

Isolated. The drumbeat continued without him on camera. Market: 65%.

Jul 21, 05:46 PM UTC · Twitter @JoeBiden

Letter: 'I am withdrawing from the race'

1:46 PM ET, Sunday. Polymarket resolved YES in 14 seconds.

Replay sessions use simulated funds against historical Polymarket price data. No real USDC moves at any point during a replay. Your simulated calibration is a training tool, not a promise of how you'll do with real money.