Over the course of 36 years in the Senate, eight years as vice president and campaigns for the White House in 1988, 2008 and 2020, Mr. Biden has become one of the most familiar faces in American life, known for his resilience in adversity as well as his habitual gaffes. And yet the avuncular, backslapping, work-across-the-aisle deal maker has struggled to translate decades of good will into the unifying presidency he promised.
Working with the…