On policy matters, it depends on what exactly congressional Republicans and the White House propose. The more they veer to the right, the easier it will be for Democrats to fight them without alienating the political middle. But Democrats could easily go too far. Some are entertaining the possibility of filibustering appropriations bills to block Trump spending plans  in essence a threat to shut down the federal government with 41 Senate votes. But shutdowns are a tactic Republicans used in 1995 and 2013, provoking political backlashes of a kind that Democrats would be wise to avoid.