Joe Biden racked up four more wins on Tuesday night, further growing his delegate lead over Bernie Sanders in what is now largely a two-person race.
Exit polls showed that several broad demographic trends that have shown up in earlier states continued to hold in Tuesday's primaries: Biden tends to perform better among women than men, for example, and Sanders tends to perform better among white voters than black voters. These results help show how Biden pulled off his wins in Idaho, Michigan, Mississippi and Missouri and continued building his momentum.
1) How Biden won Michigan
Michigan was the most-watched state of "Big Tuesday," both because it had the most delegates at stake (125) of the six states that voted, and because it was an important upset victory for Sanders in 2016, when he narrowly edged out Hillary Clinton by 1.5 percentage points.
But Michigan ended up being great news for Biden. Not only did he defeat Sanders by 16.5 points, but he did so among an energized Democratic electorate: With 100% of precincts reporting, turnout in Michigan was above 1.5 million, compared to the roughly 1.2 million who voted in 2016.
Biden improved upon Clinton's 2016 Michigan showing across a variety of demographic groups — meaning that in a mostly two-person race, Sanders' performance worsened among these groups.
While men preferred Sanders by 10 points then, they were roughly evenly split between Biden and Sanders on Tuesday. And while women preferred Clinton by 7 points then, they preferred Biden by 23 points this year.
Similarly, moderate and conservative voters preferred Clinton by 9 points in 2016. This year, they preferred Biden by 37 points.
And while black voters turned out for Clinton in 2016 and Biden this year at about the same rate, Biden performed better than her among whites. Four years ago, white voters preferred Sanders by 14 points. This year, they preferred Biden by 11 points.
These shifts raise questions about what motivated voters this year, with a self-proclaimed democratic socialist once again running against a more-moderate, establishment Democrat. While it's true that electability is playing a major role in this year's race, the results also raise the question of how much votes for Sanders in 2016 were votes against Clinton (and to what degree gender may have played into that).
2) Voters saw Biden as the best in a crisis
Against the backdrop of an escalating coronavirus outbreak, Biden came out ahead of Sanders on the question of who would be better in a crisis.
About half of Michigan voters said they thought Biden was best equipped to handle a crisis, compared to about 31% who sided with Sanders. In Missouri, Biden edged Sanders 61% to 26% on the question.
As coronavirus spreads — and concerns over the outbreak spread even faster — that question about crisis-handling may have been particularly relevant to voters.
Indeed, in Washington, the state with the most coronavirus cases and deaths, Biden performed substantially better (41%) than Sanders (24%) among voters who said they were "very concerned" about the coronavirus.
One additional point about Washington's exit polls: Because of mail-in voting, many people voted when the field was much bigger. That means the polls show significant support for Warren and Bloomberg, who have both dropped out.
3) Young voters haven't turned out to boost Sanders
Sanders acknowledged after Super Tuesday that he hadn't succeeded at bringing out enough of the young voters who tend to support him.
On Tuesday, that trend continued. In Missouri four years ago, voters under 30 made up 16% of the Democratic primary electorate. This year, they made up 14%.
There's a similar pattern in Michigan: In 2016, those young voters made up 19% of the electorate, compared to 16% this year. Thirteen percent of Mississippi's voters were under 30 this year, compared to 15% in the state's last Democratic primary. (Data was not available for Washington in 2016.)
In fact, Iowa is the only state to vote so far where exit polls show that the share of voters under 30 grew this year over 2016. In all others, that share has held steady or dropped. NBC's Steve Kornacki rounded up those numbers this week:
2016 vs. 2020: Share of Dem primary/caucus electorate under 30— Steve Kornacki (@SteveKornacki) March 10, 2020
IA 18% ('16) => 24% ('20)
NH 19% => 13%
NV 18% => 17%
SC 15% => 11%
AL 14% => 10%
MA 19% => 16%
NC 18% => 14%
TN 15% => 11%
TX 20% => 15%
VA 16% => 13%
VT 15% => 11%
It's true that the raw number of young voters may be up in some states, particularly those where total turnout has gone up. However, they have not turned out in big enough numbers to shift the composition of the electorate.
That is bad news for Sanders, who does much better among young voters than older voters. He won more than 7 in 10 voters under 30 in Michigan and Missouri alike.
Meanwhile, older voters really like Biden. Seven in 10 voters over 65 in Michigan said they voted for him, along with 8 in 10 in Missouri and 9 in 10 in Mississippi. And in both Missouri and Mississippi, older voters made up a substantially larger share of the electorate than young voters.