In the battle for increasingly tight defense budgets, the US Navy may be hard pressed to continue to operate almost a dozen supercarriers well into this century whereas smaller and cheaper amphibious assault ships could actually expand America’s strategic presence around the world. So much argued Marine Corps Commandant General James Amos this week when he warned against cutting “amphibs” in favor of more expensive shipbuilding programs like destroyers, submarines and especially aircraft carriers.

Amphibious ships, particularly of the landing helicopter dock type like the Wasp class, are able to deploy fighter jets, helicopters and Marines anywhere in the world at a moment’s notice, said Amos. They can project American military force faster and at much lower cost. Whereas total cost of construction for each Nimitz carrier was around $4.5 billion, it takes just $750 million to build a Wasp.

The recent intervention in Libya proved Amos’ point. None of the Navy’s eleven supercarriers were involved in the operation. Instead, the American contribution to Operation Odyssey Dawn was spearheaded by the USS Kearsarge and its four Harrier jump jets. The ship was on a routine deployment to the Indian Ocean when orders came to sail for the Mediterranean.

Of course, Kearsarge‘s capabilities pale in comparison to the fifty fixed-wing aircraft that a carrier brings to the fore but for a military effort that was supposed to be limited in time and scope, it did the job.

There’s good reason to question the future role of the supercarrier on its own merits. As Navy Captain Henry J. Hendrix and retired Marine Corps Lieutenant Colonel J. Noel Williams pointed out in Proceedings this May, improved long range strike and increasingly sophisticated area denial capabilities undermine the carrier’s effectiveness. “The march of technology,” they believe, “is bringing the supercarrier era to an end, just as the new long range strike capabilities of carrier aviation brought on the demise of the battleship era in the 1940s.”

Construction and development of the newest supercarrier, the USS Gerald R. Ford, is estimated to cost some $12.5 billion although the Navy reckons that there’s a good change that it will end up costing at least a billion more.

For comparison, the Congressional Budget Office estimated last month that the cost for new ship construction under the Navy’s current planning would average about $18 billion per year, or a total of $539 billion through 2041. The expense of refueling aircraft carriers as well as outfitting new ships raises that average to about $19.8 billion per year.

While the era of the supercarrier draws to a close, the United States will probably soon be challenged, for the first time in nearly a generation, for control of the seas. Since the demise of the Soviet Union, no single power has come close to matching America’s naval supremacy. China may now seek to.

To balance sea control and power projection capabilities requires an updated fleet composition, according to Hendrix and Williams; one that relies more heavily on large amphibious assault ships that are practically light aircraft carriers. The America class, currently in development, could fill that role.

At 45,000 tons’ displacement, she will slide into the water larger than her World War II predecessors and larger even than the modern French aircraft carrier Charles de Gaulle. Designed without an amphibious well deck, she will put to sea with a Marine Air Combat Element and key elements of a Marine Expeditionary Unit.

Stripped of her rotorcraft, the America could hold up to thirty F-35B short takeoff vertical landing (STOVL) attack aircraft compared to the four that are standard aboard the Wasp — a more appropriate capacity for engagement missions. That and the fact that the Navy could buy three America ships for the price of a supercarrier makes the amphib option a very attractive one. “Those ships would be the utility infielders of the fleet, providing a tremendous platform for engagement missions and humanitarian assistance/disaster relief response at one end and amphibious operations and sea control at the other.”

The effectiveness of the America hinges on the availability of the F-35B for vertical takeoff and landing. The Marines want more than four hundred of these plans to replace the Harrier but delays and design failures cast doubt upon the prospect. Before retiring last month, defense secretary Robert Gates even warned that the STOVL version could be canceled unless Lockheed Martin manages to deliver the plane by 2014.

General Amos, for his part, remains “absolutely confident” that the STOVL plane will be fixed and he chose personally oversee the new warplane’s development. It’s worth the investment, he says. “With a fully fielded fleet of F-35Bs, the nation will maintain 22 capital ships — eleven carrier and eleven amphibious assault — with fifth-generation strike assets aboard.”