512 Paths to the White House

Mike Bostock’s interactive decision tree for the 2012 U.S. presidential election visualized all 512 possible outcomes based on 9 swing states. Each path through the tree represented a different combination of state wins, with the tree’s width encoding probability.

The piece was a landmark in interactive data journalism — built with D3.js (which Bostock had created the year before), it demonstrated that web-native interactivity could make complex probabilistic information intuitive. Users could hover over any state to see how it shifted the balance of outcomes.

It established the NYT graphics desk as the gold standard for election visualization and launched a wave of interactive decision trees in newsrooms worldwide. D3.js itself went on to become the dominant library for web-based data visualization.