Bernie Sanders supporters are learning the hard way that victory favors the prepared.

In the case of New York’s closed Democratic primary, that means being super prepared, as in prepared-six-months-ago prepared. The deadline for those registered as independents or under third parties to switch to the Democratic Party was on October 9, 2015, back when the idea that Sanders would be competitive in a New York primary was implausible, to say the least. That means potentially many independent Sanders supporters are being left out in the cold, though to describe them as “disenfranchised” might be a stretch—it’s not unreasonable to ask that voters be Democrats to participate in a Democratic primary. Still, as Leah Libresco at FiveThirtyEight points out, New York makes it extraordinarily difficult for voters to change registration, the point of which is to favor incumbents. Hillary Clinton will reap the benefits of that weighted system today.