Democrats are no longer trying to ignore Robert F. Kennedy Jr. and have taken to calling him out in public after a week of controversies. National party leaders for the first time acknowledged Kennedy’s disruptive presidential bid with sharp criticism, and lawmakers met his claims of censorship head-on during his testimony on Capitol Hill. It’s a notable change from their previous approach, in which Democratic leaders and party officials hoped Kennedy would simply fade away on his own. It also serves a purpose for President Biden, who has so far been cautious about addressing his primary rival directly. “On his...