That’s become an article of faith among those opposing the US fight with Iran. The US military – the navy in particular – is indeed smaller than it should be, and much American combat power is deployed to the Middle East. There is no deployable aircraft carrier in the Western Pacific, and the sole forward-based Marine amphibious unit, the 31st MEU, is deployed to Iran.
As troubling, the Iran war is draining war stocks – especially long-range precision missiles and air-defense ordnance. It’s unclear exactly how alarming the situation is, but it is likely that the US hasn’t got what it would like to have to fight China. The USINDOPACOM commander, Admiral Samuel Paparo, suggested as much in recent comments.