There are a few political figures today more maligned by conservatives than House Speaker Nancy Pelosi, mostly because she has been so effective. From her guidance of the Affordable Care Act through Congress more than a decade ago to her steady hand through the tumultuous Trump era, she built a legacy that history will treat far better than it will her detractors. But the 82-year-old Pelosi’s decision last week to step down as the House Democratic leader is the right one, handing off to a new generation during what is sure to be a confrontational reign by a slim Republican House majority. Whoe...