The United States will reduce military spending as a share of total government expenditures over the next ten years. Both parties in Congress agreed to several hundreds of billions in “cuts” to projected defense spending levels as part of a deficit reduction effort this week while the president previously endorsed some $400 billion in cuts identified by former defense secretary Robert Gates. Can the country afford more?

Reining in defense spending has proven difficult as neither the incumbent administration nor conservatives in opposition want to jeopardize — or be perceived as jeopardizing — national security. Gates’ hundreds of billion in “cuts” wouldn’t actually reduce military spending however. These are cuts to projected spending levels or estimates while nearly all federal spending increases every year.

Since September 11, 2001, military spending has increased by almost 7 percent a year, up from $291 billion ten years ago to almost $700 billion today.

In February of this year, the Defense Department requested an appropriation of $671 billion for fiscal year 2012 which starts in September. Of that amount, $554 billion was to fund the “base” programs that constitute the military’s everyday activities, including weapons procurement and paychecks. The remaining $118 billion was requested to pay for “overseas contingency operations” or the wars in Afghanistan and Iraq along with military activity in other parts of the world including Libya and Pakistan.

The Congressional Budget Office estimated in June that in order for the military to execute its base budget plans over the next decade, it would need a total of $597 billion (or 11 percent) more than if funding was held at the 2011 level. Military spending would thus rise by almost $60 billion a year on average unless entire weapons programs are reconsidered or pay and benefits for servicemen and -women is significantly reduced.

If operations in Afghanistan and Iraq came to an end, total defense outlays would be reduced by roughly one fifth. The Pentagon would still be spending hundreds of billions of dollars on pay and benefits and housing for personnel as well as operations, maintenance and procurement though. One of the main drivers of the department’s ballooning budget projections are mounting health-care costs. The military spent $19 billion on health care for servicemen and veterans in 2001. That is up to more than $52 billion for 2012.

Gates stressed the need of “modest increases” in the fees that soldiers and their families pay into their health-care plans. He warned the Senate earlier this year that the current arrangement, “one in which fees have not increased for fifteen years, is simply unsustainable.”

Earlier, Gates also cautioned against “steep and unwise reductions in defense” in general if they were enacted because of “tough economic times or the winding down of a military campaign.” His successor, former intelligence chief Leon Panetta, even forecast “doomsday” if the military were forced to cut up to $1 trillion, telling a press conference on Friday that it would “do real damage to our security, our troops and their families and our ability to protect the nation.”

Army Chief of Staff General Martin E. Dempsey, whom President Barack Obama nominated to succeed Admiral Michael Mullen as chairman of the Joint Chiefs of Staff this year, similarly warned legislators not to cut defense indiscriminately, stating that it would be “extraordinary difficult and very high risk” to trim some $800 billion over the next ten years.

Tom Donnelly and Gary Schmitt of the conservative American Enterprise Institute worry that the president will insist on even greater reductions. They point out that $330 billion was already cut from future procurement programs in 2009 while last year, another $78 billion was sliced from the Pentagon’s budget. With an additional $400 billion in cuts, overall savings would surpass $800 billion — that is assuming a total withdrawal from Iraq and a greatly reduced role in Afghanistan after 2014.

According to Fareed Zakaria, those are sound assumptions. He writes in The Washington Post that it is hardly unprecedented for the United States to reduce defense spending as they scale back or end a military campaign. Besides, there is plenty of waste and duplication in the department that should be cut, he argues.

Defense [is] a cradle to grave system of housing, subsidies, cost plus procurement, early retirement and lifetime pension and health-care guarantees. There is so much overlap among the military services, so much duplication and so much waste that no one bothers to defend it anymore. Today, the American defense establishment is the world’s largest socialist economy.

Zakaria notes that over the past decade, when the country faced no serious national adversaries, American defense spending increased from accounting for a third to equaling 50 percent of global military spending. “In other words, we spend more on defense than the planet’s remaining countries put together.”

That may be true although the comparison isn’t totally fair. Other countries didn’t wage two wars in the Middle East while maintaining a capacity to undertake military action elsewhere. Moreover, Schmitt urges lawmakers to expect the unexpected.

Whether we like it or not, in the next few years, we will still be dealing with the conflict in Afghanistan, an aggressive and likely nuclear capable Iran, the continuing threat of Islamist terrorism, possibly a failed, nuclear armed state in Pakistan, a Putin led and revanchist Russia, a rising and increasingly assertive China, and of course the seeming never ending problem child of Asia, North Korea.

The last four presidents each sent America’s military into harm’s way for wars that were not anticipated. George H.W. Bush didn’t expect Saddam Hussein to invade Kuwait in 1990. Bill Clinton couldn’t foresee the extraordinary violence that accompanied the disintegration of Yugoslavia. Very few people expected a terrorist attack of the scale of 9/11 and when Barack Obama assumed office, he couldn’t possibly predict the Arab Spring nor did he plan to bomb Libya.

Defense spending was reduced by hundreds of billions of dollars after the end of the Cold War during the late 1980s and 1990s but it meant that the country had to invest far more, suddenly and quite unexpectedly, after 2001 when it invaded Afghanistan. It seems unlikely that the United States will wage a similar, decade long land war again soon but relatively minor interventions, like the recent one in Libya, might become more frequent across an unstable Middle East and in Central Asia.

It should be possible to constrain the growth of defense spending in years ahead, especially if lawmakers are willing to thoroughly reform spending on bases at home and restructure soldiers’ benefits, but huge reductions in procurement will inevitably affect the superiority of America’s armed forces — the very superiority that American superpower depends on.