No one can accuse President Joe Biden of failing to do his utmost to prevent a full-scale war from breaking out in the Middle East. He and his indefatigable envoys must have spent more time this year working on the Middle East than any other issue.

The intensive diplomatic efforts by Antony Blinken, secretary of state, Jake Sullivan, national security adviser, Bill Burns, CIA director, and Amos Hochstein, Biden’s man covering Lebanon, among others, were supposed not only to find a workable solution to the myriad of crises but also enhance the President’s foreign policy legacy after what has turned out to be...