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Mitt Romney's campaign is defending his concerns about the shrinking U.S. Navy, in the wake of the now-infamous "bayonets" zinger by President Obama at Monday's debate.

At the debate, Obama tried to mock his Republican rival by noting that the military uses fewer "horses and bayonets" these days, just like it doesn't have as many ships -- suggesting both are antiquated tools of warfare.

Releasing a radio ad in key battleground states this week, the Romney campaign said the president's "flippant remarks insult Mitt Romney" but also expose Obama's views about America's place in the global community.

"The state of our Navy, the state of our entire U.S. military, is crucial for America," the ad says.

The current fleet stands at 288 deployable battle force ships, according to the U.S. Navy, well below what top commanders originally wanted. The number of ships actually deployed right now is 113, while another 52 ships are en route to local operations or training scenarios. The rest of the fleet is either undergoing maintenance or sitting in port waiting for assignment.

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"We have one ship back in maintenance, one ship in training and we have one ship on station doing the work," said Russell Rumbaugh, the director of budgeting for foreign affairs and defense at the Stimson Center in Washington, D.C.  "You see how quickly when you talk about capability at sea, capability actually serving U.S. interests, every single ship is not just one marginal change for the better or for worse."

That's what has Republicans like Romney worried that current numbers and further fleet cuts could hinder the Navy's ability to protect U.S. interests and guard against terror attacks.

"That's unacceptable to me," Romney said during Monday's debate.  "I want to make sure that we have the ships that are required by our Navy."

Navy admirals' bottom line eventually came down to 313 ships, and in the end the Obama administration settled on a fleet size of 300 by 2019.

"We're already seeing maritime disputes that are becoming a bit more pointed," said Adm. Gary Roughead, the man who said 313 ships was the bare minimum needed before recently retiring.  "Presence matters. If you're there, you can help control events."

Roughead, who is now a visiting fellow at the Hoover Institution at Stanford University, said numbers do matter.

"You have to build a fleet that's balanced, that gives you what you need to be dominant," he said.  "But also you have to have the numbers and types of ships that allow you to be in the right place at the right time to represent our nation's interests."

The looming prospect of mandatory budget cuts threatens to cut the fleet by nearly 60 ships if Congress and the White House can't come to agreement before the end of the year. Analysts on both sides of the aisle say some kind of agreement to avert so-called sequestration is likely, but so far that has not come to pass.

"You start dropping down into the low or mid 200s and then I believe you're going to have to be asking the question, 'where do we not want to be?' Because at some point you simply run out of the numbers to generate a presence in those places," said Roughead.

But proponents of a streamlined Navy say ships are more capable and technologically advanced than in the past and can travel across the seas faster with greater numbers of personnel and aircraft.

"On anything that any average American citizen is going to be aware of, absolutely.  The Navy can maintain success," said Rumbaugh. "They can provide deterrents, they can provide power projections from the sea, and they can provide a presence."

More than 3,700 aircraft are part of the Navy, and ships haven't gone head-to-head with another country at sea since the world wars. Advanced technology has given the fleet a stronger off-shore presence going back to the 1990's. Rumbaugh said those facts make it easier for the fleet to do its job with the current number of ships.

"The Navy's mission shifted significantly less than the other services at the end of the Cold War, because they were already enforcing a global presence strategy."

There are far fewer ships now than there were when tensions died down with the Soviet Union in 1991. At the height of the Reagan administration, there were 529 ships in the Navy. But Romney was wrong when he said the Navy is smaller than at any time since the early 1900's. At the end of the Bush administration, while the country was engaged in wars in both Iraq and Afghanistan, the fleet stood at 278.

Obama didn't catch the inaccuracy at that time, or choose to highlight it, but the statement by his opponent is what sparked the well-reported quip.

"You mentioned the Navy, for example, and that we have fewer ships than we did in 1916. Well, governor, we also have fewer horses and bayonets, because the nature of our military's changed," the president said.

KT McFarland, a national security and Fox News contributor who served in the Reagan administration when the Navy was much larger, agrees that the nature of Navy has changed. But she said it's the country's global presence that requires a greater number of ships than what the military has now. She's talking not just about guarding against external threats, but the need for the Navy to deliver humanitarian aid around the world and act as first responders in places like Japan after last year's earthquake and tsunami.

"It's called the global force for good," she said. "People are going for medical checkups, for eye exams, they're getting issued glasses, they're having surgery they might not have access to otherwise."

A smaller Navy could also mean longer, more arduous deployments for personnel.

But in the end, the debate comes around to what most things these days do: the economy and the battle between jobs and deficits. While most agree there's just not enough money to have it all, Romney is using this issue to make his larger point in this election, tying the Navy to jobs.

"Our freedom depends on it. And so do many of our jobs," Romney said.

Fox News' Adam Housley contributed to this report.