How to Follow New York's Primaries

Republican presidential front-runner Donald Trump prepares to cast his ballot Tuesday in the New York primary. Andrew Kelly/Reuters

On Tuesday, New York voters headed to the polls to cast their ballots in the Democratic and Republican presidential primaries.

On the Democratic side, Hillary Clinton, the former secretary of state and U.S. senator from New York, hopes to shut down the momentum of her rival, Bernie Sanders, who has won in six of the last seven nominating contests.

Despite that, the Vermont senator trails Clinton by a significant number of pledged delegates and by an even larger number of so-called superdelegates—Democratic party leaders and elected officials. Sanders needs a surprising win in New York, with its 291 delegates, to close the gap. But the state's closed primary favors party loyalists over left-leaning independents: The deadline to switch parties was October 19, 193 days before the primaries. Voters who failed to switch before the deadline won't be able to vote in their primary of choice. However, the deadline for first-time voters to register was more forgiving: March 25, 2016.

For Republicans, stopping Donald Trump is the name of the game. The real estate mogul/reality TV star/personal branding savant is on his home turf in New York, where 95 delegates are at stake for the Republicans. The GOP also has a closed primary, so conservative independents may be locked out of voting if they failed to switch parties in time.

Texas Senator Ted Cruz and Ohio Governor John Kasich hope to narrow Trump's delegate lead before the Republican Convention in July. If Trump doesn't win a majority of delegates before then, the party will face a contested or open convention, in which Cruz, Kasich or another Republican could defeat him for the nomination.

The New York state Board of Elections is releasing returns on its website throughout the day. Polls close at 9 p.m. Eastern time.