1948
What it would have taken
Counterfactual arithmetic from each state’s recorded popular vote. It measures how close the result was; it does not predict what voters would have done.
California was the tipping point. Line up the states Truman carried from widest margin to narrowest: California’s 25 electoral votes are the ones that took Truman to 278, past the 266 majority. Truman carried it by 17,865 votes (0.44 points).
The cheapest set of Truman’s states that would have given Dewey a majority is Ohio, California and Illinois — 78 electoral votes. Truman’s combined margin in these states was 58,584 votes.
A margin is overturned when more than half of it switches sides, so this path would have needed at least 29,294 Truman voters to vote for Dewey instead, in exactly those states. Had that happened, the count would have been Dewey 267, Truman 225.
| State | EV | Margin | Points |
|---|---|---|---|
| Ohio | 25 | 7,107 | 0.24 |
| California | 25 | 17,865 | 0.44 |
| Illinois | 28 | 33,612 | 0.84 |
| Total | 78 | 58,584 |
Margin = the winner’s votes minus the runner-up’s in that state. Points = that margin as a share of every vote cast there.
Flipping Ohio and California (Truman’s combined margin 24,972 votes) would have left nobody at 266: Dewey 239, Truman 253. The Twelfth Amendment would then have sent the choice to the House of Representatives, voting one vote per state delegation.
That costs less than the winning path above because it needs fewer electoral votes: Dewey gains just enough to stop Truman, not enough to win.
No single state Truman carried was big enough to have elected Dewey on its own.
Electoral votes in parentheses: the block each state cast for Truman. This uses electoral votes only, not margins.
Nationally, Truman received 24,178,347 votes and Dewey 21,991,292, so Truman finished 2,187,055 votes ahead of Dewey (4.48 points). Truman won the Electoral College 303–189.
How these are defined
- Flip
- Exactly what a click on the map does: the electoral votes a state cast for the candidate who carried it move to another candidate. District and faithless electors stay as cast.
- Margin
- The winner’s votes minus the runner-up’s in a state, from the state’s recorded popular vote. Points are that margin divided by every vote cast in the state.
- Tipping point
- Order the states the winner carried from widest margin to narrowest and add up their electoral votes; the tipping point is the state where the running total first reaches a majority. Its margin here is over the next-best candidate in that state.
- Narrowest path
- Of every set of states the winner carried, the one that would have given the runner-up at least 266 electoral votes with the smallest combined margin. Found by an exact search, not by taking the closest states in order. A tie or any result short of 266 does not count as a win.
- Switched voters
- One voter changing sides moves a margin by two, so a margin of N is overturned when more than N ÷ 2 voters switch. The minimum is the sum of that, state by state. Real elections never move this neatly; this is arithmetic, not a forecast.
- No majority
- When nobody reaches 266, including a tie, the House of Representatives chooses the president, one vote per state delegation.
The map is a toy: anything you flip on it is invented. Clicking a state hands its electoral votes to the next candidate on the 1948 ballot, then to the next, and finally back to the candidate who really carried it — nothing here changes what happened.
- Only the block of electoral votes a state cast for its own winner moves. District and faithless electors stay as cast, because individual electors — not the state — cast them.
- The majority line is 266, the threshold 1948 actually used, out of 531 electoral votes.
- If nobody reaches 266, the Twelfth Amendment sends the choice to the House of Representatives — which is how 1800 and 1824 really ended.
- The address bar carries your scenario, so a link you copy opens on the same map. Reset, or a link with no scenario, restores the real result.