The U.S. military's success in helping Israel stop a massive wave of Iranian missiles and drones last weekend might suggest Washington is well prepared militarily for whatever comes next as Iran and Israel move from shadow warfare to direct confrontation.

But current and former U.S. officials say U.S. forces are not positioned for a major, sustained Middle East conflict and the Pentagon may have to revisit assumptions about military needs in the region if the crisis deepens.

"I don't think we have all the forces that we would want to support Israel if there was a direct war between them and Iran," said Michael Mulroy, a former deputy assistant secretary of defense for the Middle East under the administration of former U.S. President Donald Trump.