WASHINGTON (Reuters) - Defense Secretary Leon Panetta spelled out a doomsday scenario Monday that he said could occur if Congress fails to take action to avoid a $1 trillion cut in defense spending over the next decade.
Panetta, responding to a letter from Republican Senators John McCain and Lindsay Graham, said cuts of nearly $100 billion a year would leave the United States with its smallest ground force since 1940, the smallest number of ships since 1915 and the smallest air force in its history.
"The impacts of these cuts would be devastating for the department," Panetta wrote Monday in his letter, which was released by the senators.
Independent analysts say Pentagon spending has increased substantially over the past decade and $1 trillion in cuts over the next decade would not be out of line with similar post-war drawdowns.
But Panetta urged Congress to meet their goals for deficit reduction without reducing national security spending beyond the more than $450 billion already approved by lawmakers and President Barack Obama in August.
In addition to trimming national security spending as part of an effort to gain control over the country's $14 trillion debt, the August law created a congressional "super committee" to recommend ways to reduce federal spending by another $1.2 trillion over the next decade.
Failure to pass a compromise spending deal by early January would result in automatic across-the-board spending cuts expected to cut Pentagon spending by another $600 billion -- a result Panetta has said would be disastrous.
McCain and Graham sent Panetta a letter last week telling him that his warnings had been vague and needed to be more specific in order to help Congress understand how he views the severity of the situation.
Panetta said under the current law, failure to pass a compromise would lead to an immediate 23 percent, across-the-board cut that would have to be applied equally to all major investment and construction programs beginning in the 2013 fiscal year.
"Such a large cut, applied in this indiscriminate manner, would render most of our ship and construction projects unexecutable -- you cannot buy three-quarters of a ship or a building," Panetta wrote.
"We would also be forced to separate many of our civilian personnel involuntarily and, because the reduction would be imposed so quickly, we would almost certainly have to furlough civilians in order to meet the target," he added, saying that such a move would "seriously damage" military readiness.
Over the longer run, the Pentagon would have to impose cuts that could lead to termination of the F-35 Joint Strike Fighter, the military's largest procurement program, which aims to buy 2,447 of the radar-evading fighter jets in the coming decades.
The cuts also could force the Pentagon to end its European missile defense program, terminate its new littoral combat ship, end all ground combat vehicle modernization programs and kill Army helicopter modernization efforts, Panetta wrote.
The cuts also could affect the U.S. nuclear deterrent. Panetta said the spending limits could force the Pentagon to delay its next-generation ballistic missile submarine and get rid of its intercontinental ballistic missiles -- two systems maintained to ensure deliver of nuclear weapons if needed.
Reacting to Panetta's letter, McCain and Graham said the forced cuts would "set off a swift decline of the United States as the world's leading military power."
"We are staunchly opposed to this draconian action. This is not an outcome that we can live with, and it is certainly not one that we should impose on ourselves," they wrote.