(AP Photo/J. Scott Applewhite) Senate Minority Leader Chuck Schumer and House Minority Leader Nancy Pelosi speak to reporters on December 13, 2017. democracy_rules.jpg A fter a grueling year in the political wilderness, Democrats see a ray of hope as they close out 2017, celebrating electoral wins in Virginia and Alabama, and honing their midterm attacks on the GOP’s wildly unpopular tax bill. But lest Democrats wake up to a giant hangover next year, they would do well to make a few New Year’s resolutions before ladling out the holiday punch. Above all, they should take care not to fall into the same traps that have snarled the GOP. Democrats have assailed President Trump and his allies for tearing down democratic norms, spreading falsehoods, and catering to elites. But progressives have struggled with their own destructive impulses, sounding troubling echoes of the disruptions on the right. Intra-party feuding, “antifa” violence, overwrought hyperbole, and secret political spending...