New York City’s new mayor, Zohran Mamdani, will soon confront an ordeal that might finally knock that trademark smile off his face: balancing the budget. The city is projected to have a $5 billion deficit this year and is required by law to make up for that shortfall by raising revenue, cutting spending, or both. Mamdani has proposed large tax increases paired with modest cuts to city programs. But getting to $5 billion won’t be easy, in part because the biggest portion of the city’s budget is