The Trump Administration is blowing the whistle on the Palestine Liberation Organization, and it would be hard to identify a more overdue reality check in U.S. foreign policy.

The Administration announced Monday that it is closing the PLO’s Washington office, citing lack of progress on peace negotiations. The PLO began as a terrorist organization but was allowed to open an office in Washington in 1994 after the Oslo accords produced hope for a new era of reconciliation between the PLO and Israel.

That...