In the short term, should Joe Biden win the election and move into the White House, he would take office with a Democratic Party unified in its opposition to all things Trump. The question is how long would that last before leaders of every liberal interest group circling the new administration begin to get restless. In answer to this question, Carter Eskew, a top strategist on Al Gore’s 2000 campaign, wrote by email that Biden became a unity candidate in response to an overwhelming, almost feral desire to limit Trump’s damage to one term. When Trump leaves, Democratic unity, I...