Welcome to Washington, where on Friday Senate Democrats blocked a short-term budget proposal that would have kept the government open through November 21. Some Democratic Senate candidates are even refusing to back Mr. Schumer for another term as Democratic leader, should they themselves be elected to the chamber. Senator John Thune puts it rather simply: This will be a “Schumer Shutdown,” he declared earlier this week. Mr. Schumer has offered no insight into how far they are willing to take this. When asked if he was prepared to block a funding package that did not include any of his demands, Mr. Schumer repeatedly dodged, saying only that he wanted a negotiation.