But, more than just being a group of voters, black voters have often voted in blocs in presidential primaries. That is, black voters have voted very similarly to one another in recent competitive contests. Hillary Clinton won about 80% of the black vote in the 2016 primary. Barack Obama won about 80% of it in the 2008 primary. Although neither the 2004 or 2000 primary season went on for any extended length to fully grasp how all black Democrats felt, John Kerry and Al Gore both dominated the black vote in early contests and did better than they did with white voters. Bill Clinton won about 70% of the black vote in 1992. Jesse Jackson won over 75% of the black vote in both his 1984 and 1988 bids.

To give you a comparison of how unusual it is for such a large portion to vote as a bloc, look at college-educated white and very liberal voters. Hillary Clinton lost the median caucus or primary with an entrance or exit poll by 4 among very liberal Democrats. She won college educated whites by only 6 points in the median contest.

Voting as a bloc means that a group can be decisive. That’s exactly what happened in the last two primaries. Bernie Sanders was neck-and-neck with Clinton among non-black voters in 2016. Clinton’s large margin with African-Americans gave her an easy win overall. The shoe was on the other foot for Clinton in 2008. She easily defeated Obama among white and Latino voters. Obama’s large win with black voters gave him just enough votes to beat Clinton overall.