Seven of the last nine Democrats who won the Iowa caucuses went on to become the party's presidential nominee, including the last four.

Seven of the last nine Democrats who won the Iowa caucuses went on to become the party's presidential nominee, including the last four.

That's one reason why these complex contests in a state that's 91% white play such a key role in the presidential race: https://t.co/szsft4ttH8 pic.twitter.com/k52hJ2Caz2

— NPR Politics (@nprpolitics) February 3, 2020