There has not been a closely-contested mayoral primaries in New York City since 2013, the year Democrat Bill de Blasio was elected. Now completing his second term, the incumbent is ineligible to run this year.
This year, thirteen Democrats and two Republicans are vying for their respective party's nominations. Almost all the focus is on the Democratic side, as the winner of Tuesday's primary will be an overwhelming favorite to be elected in November.
There have been a number of significant changes in election law and administration over the past couple years that will be put to the test for the first time in a NYC mayoral election. While the overall goals are laudable - increasing turnout and finding a winner preferred by a majority of the electorate - the changes also mean it will likely be several weeks before we know who the Democratic nominee will be.