It’s hard to pin down the shape of a future administration’s foreign policy, especially so when the administration is still in the late larval stages, as Joe Biden’s currently is. Still, a picture is emerging: We’re aware of the core views of the aspiring commander in chief, hear the tenor of the rhetoric emerging from among his chief advisers, and know this group’s judgment on the legacy of the administration it hopes to replace. One challenge to the clarity of that picture is that Biden himself has been scattershot on foreign policy over a lengthy career in government: Biden served on the Senate Foreign Relations Committee for more than a quarter-century until he became Barack Obama’s vice president in 2009. Without cherry-picking contradictions from a foreign policy record that spans nearly five decades of government...