Withdrawal worked for Israel once, in 1979, when it signed a peace agreement with Egypt and left the Sinai Peninsula, which was also occupied in 1967. But that set a problematic precedent. President Anwar Sadat of Egypt insisted that Israel hand back the entire peninsula to the last inch. Israel decided that the reward was worth the price, as a major Arab country agreed to break with other Arab states and accept Israel’s legitimacy. But there was a hidden, unanticipated cost: Israel’s adversaries, in future negotiations, would demand the same kind of compensation. The 1967 line — what Israel controlled before the war — became the starting point for all Arab countries, including Syria. It became a sacred formula, worshiped by the international community.

What Mr. Trump is doing extends far beyond the ability of Israel to control the Golan Heights, to settle it and invest in it. The American president is setting the clock back to before the peace deal with Egypt, to a time when Israel could argue that the reward for peace is peace — not land.

Syria, of course, is unlikely to accept this. At least not in the short term. But maybe someday, a Syrian leader will come along who doesn’t entertain the thought that Israel might agree to return to the pre-1967 line and who will accept a different formula for achieving peace.