WASHINGTON — (CNN) Democrats in the District of Columbia on Tuesday will cast the last votes of the primary season, a contest that nevertheless will not change the general election match-up.

Hillary Clinton clinched her nomination last week, but Bernie Sanders declined to drop out and pledged to give every voter a chance to decide between the two candidates.

Though the primary is essentially over, Sanders held a single campaign event in Washington last Thursday, and he has reminded voters here about his support for statehood for the nation’s capital.

Twenty delegates are at stake in Tuesday’s primary, which is open only to registered Democrats. Delegates are awarded proportionally at the statewide and district-level, with a 15% threshold required. Polls are open from 7 a.m. to 8 p.m.

The more meaningful Democratic activity in Washington on Tuesday will be the private meeting between Clinton and Sanders.

The Vermont senator has begun signaling that his campaign is soon to close, but Sanders’ aides say he is not expected to immediately endorse Clinton.

“It should be amicable and hopefully constructive,” a person close to Sanders said of the meeting.

He is expected to renew his pledge to help defeat Donald Trump. But “he’ll also put his cards on the table” and push for progressive policy positions in the fall campaign and in the party’s platform.

This is the way to keep his movement alive — or an attempt to — without instantly alienating his core supporters, Sanders aides say.

The few Republicans in the District of Columbia gave Marco Rubio one of his few wins when they voted in March.