A president sweeps into office, promising to turn the page on an era of horror and recrimination. In foreign policy, he can redeem the United States’ promise, reversing a great country’s fall into temporary iniquity. He deserves every bit of the credit for genuine improvement. And yet, the very hostility the previous administration earned cloaks the leader of the new one with extra immunity from scrutiny: It provides a space in which, amid complacent uplift, many continuities in policy are established.