Things might chaotic get for the Democrats in 2020, FiveThirtyEight's Nate Silver showed. As more and more candidates enter the running, he argues, the more challenging it will be for establishment Democrats to break through the fold. Silver anticipates the number of "major candidates" landing somewhere between 17 and 24 before all is said and done (though only nine have officially entered the ring at this point), which would constitute the largest primary field in history.

When looking at data back to 1972, Silver considered two things — how many candidates campaigned in each primary and whether or not the party elites were able to push their preferred candidate to the forefront. The table below shows that, historically, the larger the pool, the more likely it has been for a dark horse to secure the nomination, with President Trump's 2016 victory as the most striking example.

What's happened in the past when fields are this large?



You've wound up with Trump, McGovern and Carter, all deeply unconventional nominees who lacked support from the party establishment. pic.twitter.com/FdmXSBds3g — Nate Silver (@NateSilver538) February 13, 2019

While it still remains unclear who Democratic elites might back, national polls generally have former Vice President Joe Biden (who may not even run) in the lead. But with more than half the expected field yet to even announce their candidacy, these polls probably have very little long-term significance, and history tells us predicting the eventual nominee could become even more difficult. Tim O'Donnell