After every U.S. presidential election, hope once again beckons that the new administration will be more successful than its predecessors in improving U.S.-Russian relations. The 2020 elections may finally break that pattern. Assuming that former Vice President Joe Biden takes the oath of office on Inauguration Day 2021, he will take office not as an idealistic or naïve newcomer to foreign affairs, but rather as a veteran with a well-developed sense of priorities and perspectives—and this includes a healthy dose of disillusionment with...