Transcript for Endorsements matter when there's a consensus, not yet this year: Nate Silver
No one wanted to question this system, and in 2016 he fundamentally changed politics in America. We, right now, have one of the best democratic presidential primary fields in a generation, and much of that is thanks to the work that Bernie Sanders has done in his entire life. There you see AOC endorsing Bernie Sanders at a massive rally in queens on Saturday. Sanders also picked up the endorsement of fellow squad member, congresswoman ilhan OMAR, after his energetic comeback to the debate stage on Tuesday night. But will endorsements like this be decisive in this year's primary fight. We asked fivethirtyeight's Nate silver. In 11 of 16 nonincumbent nominations since 1972, the candidate who led endorsements before Iowa wound up winning a nomination 69% of the time. Of course you can probably all think of one recent exception, Donald Trump. Trump had zero endorsements from members of congress until weeks after Iowa and New Hampshire. Instead, the endorsement leader was Jeb Bush. But Jeb got 2.8% of the vote in Iowa and trump got elected president of the United States. So, has everything changed in the age of trump? Well maybe. Endorsements used to be a way for the party establishment to weigh in, but there's more tension now between the establishment and the party basis, especially for the GOP. Also, voters have more information at their fingertips and more ways to participate in the political process, like on social media. That can allow voters to take the process into their own hands, whether the establishment likes what they do or not. Just one more thing. If you look at endorsements this year, they suggest the democratic primary is still wide open. Joe Biden leads in endorsements in fivethirtyeight's tracking but he has only about 25% of them so far. Second is kamala Harris and third is Cory booker. Warren is just fourth by contrast, and Sanders, even with new endorsements this weekend, is stuck in sixth place. So I find that endorsements matter when there's a consensus of them that point clearly in one direction. This year there's not, at least not yet. It's as though Democrats are telling their voters you're going to have to decide on this nominee for yourself. Kind of the way it goes. Nate, thanks very much. You can read more of Nate's 2020 analysis at fivethirtyeight.com. Our roundtable is up next.
This transcript has been automatically generated and may not be 100% accurate.