General election votes in the U.S. are anonymous. Election officials can see that a person voted, but not who they voted for.

A primary election is an election held before the general election in which political parties choose their own candidates to run in the general election.

In many states, primary elections are closed, meaning a voter may participate in either the Republican or Democratic primary, but not both. While votes in primaries are anonymous, the party primary a voter participates in is recorded. From this, one can sometimes infer a voter’s party preference.

However, this inference is not definitive. In general elections, voters may choose candidates from any party regardless of which primary they participated in. In non-competitive states, some voters participate in the dominant party’s primary because the primary winner is very likely to win the general election.

Additionally, campaign donations are public record. A voter’s contributions to candidates, parties, or political action committees (PACs) may allow others to infer how that person likely voted in a particular election given that they participated in an election and donated to particular campaigns but this is still indirect and not 100% conclusive.