It’s been more than a month since Democratic contenders Hillary Clinton and Bernie Sanders held a debate. Tonight’s faceoff in Brooklyn pits the New Yorker by birth versus the New Yorker by choice in what might be their final battle. The debate will be a chance for the candidates to respond to some recent incendiary rhetoric, most of which came from Sanders: calling Clinton “unqualified” to be president; questioning her taking money from Verizon for a speech as both candidates appeared at union picket lines to support striking Verizon workers; and the comment “corporate Democratic whores” by a speaker at a Sanders event to describe those who, like Clinton, support incremental progress in health care reform. After the debate, it’s all about numbers. Sanders may have won seven of the last eight Democratic contests, but he still trails Clinton by 251 pledged delegates — four more than the number at stake in Tuesday’s New York primary. The Democrats have no “winner-take-all” contests. Delegates are allocated proportionally to the popular vote. So, in order for Sanders to catch Clinton, he needs to win about 60% of the vote in New York and the 19 other remaining contests. It’s a high mountain to climb.