The immigration deal foundered yesterday, on the verge of collapse under its own weight just days after it appeared to have a clear path to pass the Senate. By late in the afternoon, Republicans were accusing Democrats of trying to "stuff" them, and Democrats said Republicans were trying to kill the bill by obstructing the process. Both sides were saying they don't know whether the process can be put back on track. A showdown is scheduled for tomorrow, when Democrats said they will force a vote to set a time limit on the bill, and Republicans have promised to block...