By Kristina Wong

The Navy’s 272-ship force is straining under today’s security challenges, some experts say — and one glaring symptom is a shortage of aircraft carriers.

For the first time in almost a decade, the Navy does not currently have a single aircraft carrier in the Persian Gulf area to execute the war against the Islamic State in Iraq and Syria (ISIS), or to keep Iran in check.

There was also an interruption to what is billed as a “continuous carrier presence” in the Asia-Pacific region after the USS George Washington left in July and its replacement did not get there until the fall.

Earlier this week, senior Navy officials publicly acknowledged there will be more gaps next year. The basic problem is simple: The Navy only has 10 aircraft carriers, one short of what senior officers say is required.

“We require 11 aircraft carriers to meet our full range of military operational requirements,” the Navy’s Assistant Secretary for Research, Development and Acquisition, Sean Stackley, told the House Armed Services Seapower and Projection Forces Subcommittee on Wednesday.

“Today we’re at 10 — and we’re at 10 that are highly stressed because they have been driven hard,” Stackley said.

An 11th aircraft carrier, the USS Gerald R. Ford, is slated to be commissioned in 2016, but won’t be ready to deploy until 2021.

This shortage also comes at the same time U.S. leaders are attempting to reassure Gulf Arab allies that they are willing and able to counter growing Iranian influence in the region. The day after the USS Theodore Roosevelt left the Persian Gulf on Oct. 9, Iran fired off a ballistic missile in violation of international law.

Officials say the carrier shortage is due mainly to deferred maintenance on the carriers, to accommodate repeated deployments in support of the Iraq and Afghanistan wars. The longer a carrier goes without being maintained, the longer maintenance will take when it’s finally done. That backlog of maintenance was then exacerbated by steep defense cuts under sequestration.

Currently, half of the 10 carriers are in maintenance. With three carriers supporting every one carrier deployed, it is impossible to have two continuously deployed in both the Middle East and the Asia Pacific at the same time.

But it’s not just carriers that are stretched thin, it’s the whole Navy fleet, according to naval expert Seth Cropsey, director of the Center for American Seapower at the Hudson Institute.

“The Navy is strained because the number of ships is down from where it was five, 10, 15 years ago, and the numbers of missions that it has, has increased from five, 10, 15 years ago,” said Cropsey, who served as deputy undersecretary of the Navy for Republican Presidents Ronald Reagan and George H.W. Bush.

The Navy itself has pushed back against the notion that it is strained.

“We’re focused on being present where it matters, when it matters and ensuring the force is employed in a sustainable, affordable way,” said Navy spokesman Lt. Cmdr. Tim Hawkins. “But make no mistake, we are still meeting our global commitments.”

Retired Marine Col. Mark Cancian disagrees. Cancian served as the chief of the Office of Budget and Management division that works on the Pentagon’s budget from 2008 until April 2015.

“There’s no question that the Navy is strained,” said Cancian, who is now a senior adviser of the International Security Program at the Center for Strategic and International Studies. “Strained in the sense that the combatant commanders want more naval presence than the Navy can give them.”

The Navy is attempting to reach a goal of 303 ships by 2021.

Cropsey argues “the absolute minimum is somewhere around 325 ships. … If we are serious about the threat that’s increasingly coming from states like China, Iran, Russia and North Korea, specifically their efforts to deny access to the waters in their area, we need closer to a 350-ship Navy.”

The requests actually made by the combatant commanders are usually kept private.

But Rep. Randy Forbes (R-Va.), chairman of the House Armed Services Seapower and Projection Forces Subcommittee, said during Wednesday’s subcommittee hearing that combatant commanders would hypothetically request 21 aircraft carriers.

Forbes is a consistent advocate of robust military spending whose district abuts cities, including Norfolk and Hampton, that are heavily dependent upon the Navy.

“The answer is we need more,” added Bryan McGrath, deputy director of the Center for American Seapower at the Hudson Institute.

McGrath noted that during World War II, the United States had around 3,000 ships, including about 50 aircraft carriers. That number dropped down to 700 during the Vietnam War. The numbers dropped further soon afterward, he said.

Former President Ronald Reagan made it his goal to build a 600-ship Navy — getting to 594, including 15 aircraft carriers. After the Cold War, the numbers plummeted further. Still, he said, a review during the Clinton administration called for 365 ships.

“And that was during an era for little or no great-power tension … I think we are beginning to enter an era of renewed great-power tension. In my view, we have a Navy that is not appropriately sized for our part of the bargain,” McGrath said.

He noted the argument by some that ships are only becoming more vulnerable as enemies improve their capabilities, but he said that was true of every arsenal.

It’s not clear whether calls for more ships may be heeded. Fiscal hawks and skeptics who believe the Pentagon has sought more funding than it actually needs have pushed back against increased defense spending.

Calling for more ships has become a popular Republican talking point.

New House Speaker Paul Ryan (R-Wis.) mentioned building more ships during a recent interview on the Hugh Hewitt Show. And several Republican presidential candidates have sounded similar notes.

But Cancian said it’s not just a GOP talking point.

“The current strategy calls for a very forward engaged military, a lot of forward presence, and our allies and partners expect that.” he said. “In the Middle East, particularly now you’d like to be reassuring your allies and partners.”

Cancian also argued that ships provide a more forceful U.S. military presence than other forces.

“Flying a couple of airplanes into an airbase just doesn’t give the visibility that sailing a ship into a harbor does,” he said. “There’s nothing like sailing a carrier into someone’s harbor to make the point that the United States is here.”