As Nancy Youssef and Gordon Lubold reported on Monday, the U.S. has had no carrier strike group in the Persian Gulf since March. That the Navy has had no keystone presence in the Gulf even as U.S.-Iran tensions rise has some concerned.

But here's the thing: The U.S. no longer needs a carrier in the Persian Gulf to constrain and counter Iran.

The F-35 Joint Strike Fighter is why — more precisely, the F-35B variant's ability to perform vertical takeoffs and landings on the Navy's Wasp-class and America-class amphibious assault vessels. That ability enables the Navy and Marine Corps to employ exceptional air and ground strike aircraft without using an aircraft carrier. In operational terms, it means the U.S. has new means of dominating enemy aircraft and in supporting allied forces on the ground. The critical factor here is that the F-35B is far more capable in air-to-air combat than the platform which it replaces, the Harrier jet. In fact, in global terms, the F-35Bs are only outmatched only by other F-35 variants and the F-22. So where the amphibious assault vessels have previously had to operate absent a potent air-to-air threat, they can now operate just about anywhere.

Guess where the U.S. currently has one such vessel?

Very close to Iran. The USS Essex is in the Arabian Sea just south of the Persian Gulf. And as with most deployed amphibious assault vessels, the Essex is carrying a Marine Expeditionary Unit. Consisting of more than 2,100 Marines, and a complement of tanks and armored vehicles, this MEU also consists of F-35Bs from Marine Fighter Attack Squadron 211. That squadron recently carried out strikes on the Islamic State in Afghanistan, but could also destroy Iranian ground, air, or naval targets if needed.

More broadly, the F-35Bs significantly boost the navy's power projection capability. After all, when all the Navy's 9 amphibious assault vessels are eventually equipped with F-35Bs, they'll complement the Navy's 11 aircraft carriers. Although the aircraft carriers can carry many more jets than the amphibious assault ships, taken together they'll give the U.S. an air-superiority-plus-ground-strike carrier strength of 20 ships. That's a very powerful deterrent. But it's also a good reason for the Navy to refocus its resources toward building submarines. This matters because the navy's submarine fleet is currently too small. And submarines are especially crucial towards deterring China's rapidly growing threat.

In short, with regards to Iran and elsewhere, the F-35B has changed the naval power projection game.