UPDATE (June 9): We are no longer keeping track of primary endorsements, as both Donald Trump and Hillary Clinton have clinched their respective nominations.

UPDATE (May 23): Donald Trump, who didn’t receive his first endorsement until three weeks after the Iowa caucuses, is the presumptive Republican nominee for president. Trump will enter the Republican National Convention with the fewest primary endorsements — by far — of any major party nominee since at least 1980. With Trump as the last GOP candidate remaining, any additional endorsements for him will be for the general election, not the primaries. As such, we won’t be listing those endorsements on this page.

Before any votes are cast, presidential candidates compete for the support of influential members of their party, especially elected officials like U.S. representatives, senators and governors. During the period known as the “invisible primary,” these “party elites” seek to coalesce around the candidates they find most acceptable as their party’s nominee. Over the past few decades, when these elites have reached a consensus on the best candidate, rank-and-file voters have usually followed.

Of course, not all endorsements are equally valuable. We use a simple weighting system: 10 points for governors, 5 points for U.S. senators and 1 point for U.S. representatives (there are roughly five times as many representatives as senators and 10 times as many representatives as governors).