Hillary Clinton is set to clinch the Democratic Party’s presidential nomination Tuesday as voters in six states head to the polls to cap an extraordinarily wild presidential primary.

What states vote?

California, Montana, New Jersey, New Mexico, North Dakota and South Dakota hold primaries for both parties. Democrats in North Dakota also will hold a caucus.

How close is Clinton to winning?

With her victory over the weekend in Puerto Rico and U.S. Virgin Islands votes, Clinton needs only about two dozen delegates to lock up the 2,383 she needs for the nomination. Her total includes at least 548 party elites, known as superdelegates, who have helped her build a nearly insurmountable lead over Vermont U.S. Sen. Bernie Sanders.

Does Sanders have any chance?

Sanders has vowed to continue his fight for the party’s nomination beyond Tuesday by persuading the superdelegates pledged to Clinton to switch to his camp with the argument that he matches up better against Republican presumptive nominee Donald Trump. That seems an unlikely prospect for Sanders, who has only 46 superdelegates in his column, as many of Clinton’s supporters in Georgia and elsewhere have flatly refused to flip to Sanders’ side.

Why is the vote in California still important?

California is the biggest electoral prize in November, and if Clinton fails to beat Sanders there on Tuesday, it will revive questions about her strength as a candidate in the November race. Trump has pounced on Clinton’s struggle to put away Sanders, and Democrats are worried that the liberals, millennials and party newcomers who have flocked to Sanders won’t stick with Clinton.

But under similar circumstances in 2008, Clinton defeated Barack Obama in California but failed to halt his run to the Democratic nomination and eventually the presidency.

What about the Republican race?

Trump stitched up the Republican nomination in May after his last remaining rivals dropped out of the race. But he’s held rallies across California and New Mexico in recent weeks to try to drive up his delegate total, open new lines of attack against Clinton and stay in the media spotlight.

Is this the end of the primary?

Technically, no. The District of Columbia is holding a Democratic primary June 14 with 20 delegates at stake.