It’s always a good idea to pay attention to Nancy Pelosi and to judge where things are going by which direction she’s nudging them in, but that was especially true over the past few weeks. When she started sending President Biden signals that he should reconsider his candidacy, I felt almost certain that he’d eventually do so, because she was both giving other Democrats permission to break ranks with him and letting him and his allies know the extent and inevitability of the rebellion.And I realized that Vice President Kamala Harris wouldn’t face any competition for the Democratic nomination when...