"How ironic it is, then, that it took the collapse of U.S. leadership to inject unity and action into much of the GCC and the broader Arab world," Mr. Rubin said. "Once the United States is cast aside, however, it will never restore the influence it once had. Successive presidents had Riyadh on speed dial when a crisis came, but no longer will the Saudi kings answer that 3 a.m. phone call. Ditto Cairo. Same with Abu Dhabi."