A lot of people are asking how she pulled it off. Like many shocking victories, there probably isn't one cause.

But a number of the different factors that likely catapulted Ocasio-Cortez tell us a lot about where the Democratic Party is and could be heading for the 2020 presidential nomination.

A diversifying party

Democratic candidates need to appeal to minority voters with increasingly urgency.

One of Hillary Clinton's big problems in 2016 is that she didn't turn out nonwhite voters at the same level Barack Obama did during his general election campaigns. She did, however, win her primary against Bernie Sanders in large part because nonwhite voters cast ballots for her in large numbers over Sanders.

In Ocasio-Cortez's case, she was a Latina woman running in a district where over two-thirds of citizens of voting age were nonwhite. As of this Congress, there were only three other white representatives in districts with a higher minority population than New York 14. Two of those (Gene Green and Beto O'Rourke) are leaving the House.

White voters now make up less than 60% of Democrats nationwide, according to the Pew Research Center. That's down from 67% in 2007 and 75% in 1997.

Victories like Ocasio-Cortez's are an example of why many people think that California Sen. Kamala Harris is a formidable national candidate heading into 2020.

A more progressive party

Ocasio-Cortez ran to Crowley's left. She was an unapologetic Democratic Socialist who wants to eliminate Immigration and Customs Enforcement and wants Medicare for all. Crowley had a more liberal record than most of his Democratic colleagues . It wasn't enough.

The ability for Sanders to get over 40% of the Democratic primary vote in 2016 was at minimum a sign that a high percentage of voters was willing to vote for a candidate on the leftward edge of the American political spectrum.

That shouldn't be too much of a surprise because Democratic voters are becoming a lot more liberal. According to Gallup , self-identified liberals made up 50% of Democrats in 2017. That's up from 40% at the beginning of the decade and 31% at the beginning of the decade before that.

Being more progressive goes beyond just being anti-Doanld Trump. Yes, being against Trump is usually a given. Crowley voted against Trump more often than the majority of House Democrats. Ocasio-Cortez's win was likely about more than being against Trump.

It's certainly conceivable that someone who isn't very liberal could win the Democratic nomination in 2020. It will be difficult, however. We saw Clinton tack to the left in 2016 because she felt the pressure on the left from Sanders. Expect the pressure to be even greater on Democrats heading into 2020.

A young party

One of the biggest differences between Ocasio-Cortez and Crowley was their age. Ocasio-Cortez is just 28 compared to Crowley who is 56. Crowley is actually one of the youngest members of the Democratic leadership in Washington. House Minority Leader Nancy Pelosi is 78 and Senate Minority Leader Chuck Schumer is 67.

Ocasio-Cortez is the latest young upstart to win on the Democratic side this season. Democratic nominee Abby Finkenauer in Iowa's first district is only 29. Rep. Conor Lamb is just 34.

You don't need to be young to appeal to youth voters (as Sanders showed), though it can't hurt. Young voters are a larger a part of the Democratic Party (20%) than they have been in the last 20 years per Pew. That's still a minority, but it's one that has showed itself to be willing to vote in a bloc in presidential primaries.

If Democrats are looking to draw the strongest contrast with Trump in 2020, a younger candidate might be the ticket. In 2016, Clinton and Sanders were both over 65.

The fact that Jason Kander (before deciding on a run for mayor of Kansas City) got so much buzz, despite never winning political office, gives you the understanding that there is certainly an appetite for younger candidates.

A women-led party

One way in which Ocasio-Cortez's win lines up perfectly with other primaries from this season is women have been dominating men. Usually, that has been confined to open seat races , though it came against an incumbent on Tuesday in New York's 14th.

The gender gap was exploited by Clinton in her 2016 win against Sanders.

The 2016 general election featured the largest gender gap on record for a presidential general election. The gap has maintained itself today with only 30% of women approving of Trump's job performance in the latest CNN poll compared to 48% of men. If Democrats win back the House in 2018, it will be because of large support from women.

The 2020 campaign could feature that same anger that women have against the Trump presidency. Democrats seem to want women to take Trump down. That's part of the reason why women candidates like Harris and New York Sen. Kirsten Gillibrand are getting a lot of buzz.

A more independent party

Perhaps the most controversial statement of Ocasio-Cortez's campaign was when she didn't commit to backing Crowley if she lost the nomination. Maybe it shouldn't be too surprising that she was still able to win given that Sanders, himself, isn't even a Democrat and yet did quite well in 2016.

This independent spirit fits well with the polling data. The percentage of Americans calling themselves independents is at a near record high at 42% in Gallup's 2017 average. Now many of those independents lean toward one party or the other. Still, about 40% of Democrats initially identified as independents and only said they were Democrats when pushed. That's a higher share than has usually been the case over the last three decades.

This could mean that Democratic primary voters will be more willing to go with someone who doesn't toe the line with the establishment. We already saw how more independent voters affected the Republican primary in 2016 in going with an outsider.