It takes 60 votes to pass appropriations legislation, but only 50 votes to pass a rescission package clawing appropriations back. Rescission authority has rarely been used in practice, because passing rescissions on a party-line vote blows up the logic of bipartisan appropriations. But Republicans have, for the first time ever, done party-line rescissions, and the administration has further pushed the procedural envelope with unprecedented pocket rescissions. Trump is now asking Democrats to provide cross-party votes for appropriations that they can unilaterally backtrack on and not even offering verbal promises to refrain from doing this. This is why the government is shutting down.