Joe Biden leads President Donald Trump nationally and is running ahead or even with him in most swing state polls. He is besting Trump on just about every question atop voters' minds, from the coronavirus and health care to "law and order." And yet, for many Democrats a constant anxiety -- that somehow seems to spike with each dose of good news -- persists. Four years on from Trump's stunning victory, the psychic wounds of Hillary Clinton's loss remain fresh. When a flurry of new polls were released this week that showed Biden's advantage widening, the collective reaction from liberals,...