One of the most frustrating parts of a simple plurality election is the spoiler effect. If a new candidate with marginal support enters a race, it’s possible to harm their own political cause by taking votes away from the existing candidate closest to their own positions.

It’s rarely if ever possible to be certain that voters supporting a minor candidate would have voted for a major candidate; however, we can identify the cases in which it seems likely to have made a difference.

The Electoral College system makes identifying spoiler effects particularly…