In 2016, Super Tuesday was the beginning of the end for Bernie Sanders, as returns came in from primarily Southern states.

This Super Tuesday will likely be very different.

For one thing, this Super Tuesday is a lot bigger: One-third of the total delegates will be allocated in contests today. The two largest states (California and Texas) in the country vote today, along with the 10th (North Carolina) and 12th (Virginia). Two of those states, California and North Carolina, are new additions to Super Tuesday.

For another thing, Sanders is expected to win California — possibly by a big margin — and stay competitive in or even win Texas.

Today’s also the first time Michael Bloomberg will appear on ballots. He’s spent hundreds of millions of dollars on advertising over the last few months for this day. He will likely be competing in many states with Joe Biden, fresh off his decisive win in South Carolina, for the votes of more moderate Democrats. This will also be the first set of contests without Pete Buttigieg and Amy Klobuchar, though they will remain on the ballot and have already received votes in states with early voting.

Sanders is pretty likely to come in first or second in almost every state, if not every state, which could be significant — especially if he splits those results with four different candidates.

Here are a few things to understand about Super Tuesday, as you watch returns come in:

You will hear a lot of talk about delegates in the coming weeks. To win the Democratic nomination automatically, a candidate needs to win a majority of the delegates awarded by the states. That’s unlikely to happen (though still possible). So the margins between the candidates, and all the little delegates they pick up along the way, will be important.

States generally award delegates in two ways: based on the total statewide results and by congressional district. In both state and district, the party awards delegates to candidates who earn at least 15% of the vote.

Some states vote by mail, most notably California, which means the specific delegate results in the state may take days or even weeks to determine.

Why?

If a few candidates are at 16% and 14% statewide, it could take a while for California to determine how the delegates will be awarded. If Sanders wins California and no one else clears 15% statewide, he would probably come close to winning 400 delegates. If Sanders wins California and two other candidates clear 15%, he would still win a lot of delegates, but the proportions would be reduced.

This same exercise — determining who clears 15% — will play out across the congressional districts in California (and all the other Super Tuesday states). Those results may not be the same as the statewide ones. For example: The results will probably be different a) statewide in California, b) in a congressional district that’s in Los Angeles, c) in a Silicon Valley–area congressional district, and d) in a congressional district that covers a farming area in California. It’s complicated and can take time.

The general point is: Look for the winners in these states voting today, but remember that when it comes to delegate totals, the results might look a little different from what you’re expecting.

States that close at 7 p.m. ET

Vermont (16 delegates)

Bernie Sanders will win this state and probably take all the delegates.

Virginia (99 delegates)

This is a state where Biden, Bloomberg, and Sanders will all be looking to do well — but especially the first two. Virginia’s largest population is in the Washington, DC, suburbs of Northern Virginia. This area is now reliably Democratic, but is also where more center-left and moderate Republicans have done well in local contests. Black voters and military voters also play an important role in Virginia elections, primarily in the Richmond and Norfolk areas.

States that close at 7:30 p.m. ET

North Carolina (110 delegates)

This is the fourth-biggest state on the map Tuesday and with some of the most split polling: It’s hard to know who will win, and it will be interesting to watch! Biden is hoping to do well in North Carolina on the strength of his South Carolina win; black voters and more moderate, conservative Democrats play a key role in elections here. Sanders, however, has campaigned hard in the state, especially on college campuses. Bloomberg has also invested heavily in the state.

States that close at 8 p.m. ET

Alabama (52 delegates)

This is one of the Southern states that Joe Biden hopes to win, based on the strength of his performance in South Carolina, where older black voters and older white moderates powered him to a big win. Bloomberg is also looking to do well here.

Tennessee (64 delegates)

Likewise, Biden is hoping to do well in Tennessee, another Southern state where more moderate white voters and black voters are likely to account for a big part of the electorate. Bloomberg is also looking to do well here.

Texas (228 delegates)

Democrats dream of using Donald Trump’s unpopularity to activate the nonvoters in the state and turn Texas blue on the strength of its large population of young, Latino, and black voters. In 2018, Beto O’Rourke came close to making part of that happen in a race against Ted Cruz. Where Texas Democrats did win, however, is in the affluent suburbs of Houston and Dallas.

The polling in Texas is a little all over the place. Some polls put Bernie Sanders up by a fair amount in the state, on the strength of his popularity with Latino voters, and younger voters of all races. He’s spent a fair amount of time in the state. Bloomberg has spent big here. Biden is hoping to be above the 15% mark. And lastly, this is one of the states where Elizabeth Warren is staking her longshot strategy to stay in the race. She’s spent a fair amount of time, and a lot of early organizing energy, in the state where she lived and worked. Her campaign’s thinking is that if she can place in Texas and California, she can amass a small, but important delegate total.

Oklahoma (37 delegates)

There hasn’t been a ton of polling here, and both the moderates and the progressives have a case to make. Warren, a native Oklahoman, is also hoping to secure some delegates.

Massachusetts (91 delegates)

Sanders and Warren are both trying to win outright in Massachusetts, the state she represents in the Senate, and a New England neighbor to Vermont. Despite all the “ooh drama” takes about Sanders campaigning here in recent days, this is the fifth-largest state on the Super Tuesday map, and Sanders would like to pick up as many delegates as possible in a traditionally liberal state.

Maine (24 delegates)

Sanders is hoping to win this New England state as well, though it has a flinty moderate streak (Maine is sometimes a general election battleground state), and it’s one where Pete Buttigieg had previously looked to do well, so someone like Warren or Biden may benefit.

States that close at 8:30 p.m. ET

Arkansas (31 delegates)

Biden and Bloomberg will both be looking to win. This is a Southern state, but one where Sanders may do a little better than he’s done in other Southern states. He still pulled in 30% of the vote in 2016, despite the long legacy of the Clintons in Arkansas.

States that close at 9 p.m. ET

Colorado (67 delegates)

Sanders is expected to win Colorado by a potentially substantial amount. Though the state has only recently become blue in general elections, Coloradans recently elected Jared Polis, one of the most progressive governors in the country. Sanders will also likely benefit from his strength with young white voters, young Latino voters, and liberal bros. Warren is hoping to clear the 15% threshold here.

Minnesota (75 delegates)

This one changed on Monday, when Amy Klobuchar, who has never lost a statewide race in Minnesota, ended her campaign to endorse Biden. Sanders also polls strongly in the state and held a rally there on Monday night. It’s a big state — the sixth largest on Super Tuesday — so the results matter.

States that close at 10 p.m. ET

Utah (29 delegates)

One wild card in Utah: This is a state where Buttigieg polled well, and where Bloomberg has too. With Buttigieg out of the race and Bloomberg potentially a little damaged in recent weeks, will Biden benefit? Will Sanders? Sanders is hoping to win by a fair amount here.

States that close at 11 p.m. ET

California (415 delegates)

Some polling has Bernie Sanders winning California by 15 or 20 points. If that actually happens, it will have an enormous effect on the race. He’s campaigned extensively on combating climate change and changing US immigration policy — two core issues important in California. His organizing strength in Nevada with Latino voters, a yearlong campaign to make their concerns a priority and activate that voter group, make his campaign the one to beat in California. Unlike 2016, his campaign has also spent a lot more time attuned to the delegate race, focusing on parts of the state that deliver delegates but don’t always get visited as much. If he wins big, this will be a big part of the reason. If he doesn’t win as big as he’d hoped, though, that could promise big issues in March for the Sanders campaign as the field starts to consolidate.

Warren and Bloomberg are also hoping to clear 15% here statewide, and though Biden is unlikely to do so, that would be huge for his campaign. One thing to watch: Voting in California started on Feb. 3 (the day of the Iowa caucus). A decent share of the vote has already been cast — probably some of it for Buttigieg and Steyer, who are no longer in the race.

Also voting on Tuesday

American Samoa (6 delegates)

These are caucuses and there’s been no polling, so who knows! Let’s find out.