The U.S. armed forces have spent the past decade fighting two of the largest counterinsurgency campaigns in their history. In Iraq, they have dramatically reduced the threat from al-Qaeda and Moqtada al-Sadr’s Mahdist Army, and they are now in the process of doing the same to the Taliban and the Haqqani Network in Afghanistan and Pakistan.

But just as they are drawing down in both Iraq and Afghanistan, they have met an opposing force that might prove more formidable than any of those terrorist groups. These adversaries do not carry guns and do not plant IEDs. They wear green eyeshades and wield complex spreadsheets, and with these tools alone they have the potential to devastate our armed forces—and, if left unchecked, will do more damage to their fighting capacity than the Taliban, al-Qaeda, or any other external foe could inflict.

As the comic strip Pogo famously put it in another context, “We have met the enemy, and he is us.”

Shortly before Thanksgiving the congressional “supercommittee” charged with finding $1.2 trillion in budget cuts gave up and admitted failure. Under the terms of the budget deal struck in August 2011 to raise the debt ceiling, there must now be $1.2 tillion in automatic, across-the-board cuts to the federal budget, with half hitting defense and the other half domestic programs. (Social Security and Medicare are exempt.) This draconian “sequester” was supposedly designed to frighten the members of the supercommittee and compel them to find cuts to ensure it did not come to pass. They didn’t, and now the sequester will come to pass if there is not a major policy reversal before the beginning of 2013.

This came about during a year in which defense spending had already been substantially reduced, with roughly $450 billion in cutbacks over 10 years. Hundreds of billions more will be gone from Pentagon coffers due to the fact that funding for Overseas Contingency Operations will vanish to nothing as we wind down operations in Iraq and Afghanistan. In all, the defense budget could shrink by 31 percent over the next decade, according to Todd Harrison of the Center for Strategic and Budgetary Assessments. That compares with cuts of 53 percent after the Korean War, 26 percent after the Vietnam War, and 34 percent after the Cold War.

Some might argue (and have argued, and will continue to argue) that there is nothing wrong or damaging to the United States in this, that we always downsize our military after the conclusion of hostilities. But it is beyond bizarre that we are rushing to spend the peace dividend at a time when we are not actually at peace. Hostilities have not yet ended, as our troops are still in combat every day in Afghanistan and continue to conduct military operations against Somali pirates and al-Qaeda terrorists that put them in harm’s way on a regular basis. But leave that aside, and simply consider the consequences of past drawdowns.

After the American Revolution, the size of the military plummeted from 35,000 men in 1778 to 10,000 by 1800. As a result, the nascent republic was ill-prepared to put down the Whiskey Rebellion, fight the quasi-war with France, repress the Barbary pirates preying on our shipping, and, most spectacularly, defend the new national capital from British attack in the War of 1812. The burning of the White House stood as a melancholy testimony to the consequences of military unpreparedness.

Yet we made the same mistake after the Civil War, when for a brief moment we deployed the largest military in the world. The federal armed forces fell from more than a million men in 1865 to merely 50,000 in 1870. Luckily we did not face a foreign attack in the postwar decades. But we did face the challenge of Reconstruction. Its failure was made inevitable by the inability (or unwillingness) of Presidents Andrew Johnson and Ulysses S. Grant to station enough federal troops in the South to repress the Ku Klux Klan and to enforce the guarantees of equality contained in the newly enacted 13th, 14th, and 15th Amendments. By 1876, the federal troops were all withdrawn and the era of Jim Crow had begun. The full promise of Reconstruction would not be realized for another century.

If we discount the Indian Wars (the main focus of the U.S. Army from 1865 to 1890), the next major conflicts we faced were the Spanish-American and Philippine Wars. Our Army, which in the late 19th century numbered only 25,000 men—smaller than the New York Police Department today—was unready for both conflicts but did not pay too high a price for its unreadiness because of the poor condition of its enemies (the decrepit Spanish army and the meagerly armed Filipino insurrectos).

The costs of our unreadiness for the Great War were also somewhat masked, this time by the considerable capacity of our allies, Britain and France, whose veteran armies provided on-the-job training, leadership, and support for newly mobilized American doughboys. But after World War I, both Britain and France were so drained by their exertions that they could not effectively police a fragile peace. And neither could we—not when our armed forces were shrinking in number from 2.9 million men in 1918 to 250,000 in 1928. Even if we had wanted to remain committed to European security, we did not have the resources to do the job. Our abdication of leadership made a second world war more likely and, when it came, practically guaranteed that we and our allies would lose the early battles. Both the Nazis and the Japanese might have been deterred from aggression if they had had to face large numbers of forward-deployed American forces. But they did not, and so they were led to believe that launching wars of conquest could pay off.

With the lessons of the 1920s and 1930s fresh in their minds, American statesmen in the late 1940s were determined to maintain a presence in Europe. But they also responded to the war-weariness of the country by demobilizing so rapidly that the ranks of the armed forces shrank from a wartime high of 12 million men to just 1.4 million by 1950. Not coincidentally, that was the year that Kim Il-sung chose to launch an invasion of South Korea, confident that the American armed forces would not stand in his way. He was almost right. The terrible experience of Task Force Smith, the first American Army unit thrown against the North Korean juggernaut, still makes for sad and sobering reading: The task force was made up of soldiers who did not have enough training or even ammunition, and they were brushed aside with heavy losses by the invaders. Eventually the U.S. recovered half the peninsula, but only at the cost of 36,000 dead Americans—a toll that might have been avoided or at least lessened if we had kept a substantial force in South Korea in the first place to deter Communist aggression.

The decline in the size of the armed forces after the Korean War buildup was less drastic than after World War II (we went from 3.6 million men in 1952 to 2.5 million in 1959), but the Army still lost almost half its active-duty strength in the 1950s. President Dwight D. Eisenhower was enamored of a New Look strategy that sought to minimize conventional forces in favor of nuclear forces. This was the era of the “pentomic army” equipped with weapons such as the Davy Crockett nuclear launcher. That may have sufficed to deter a Red Army invasion of Western Europe, but it did nothing to prevent the Soviet Union and Red China from pursuing proxy wars against the United States, most successfully in Vietnam. This was not a conflict we were well prepared for, and we paid a high price for unpreparedness—the U.S. consistently lost ground to the Viet Cong and the North Vietnamese Army from 1964 to 1968. By the time the U.S. troops staged a post–Tet resurgence under the leadership of Gen. Creighton Abrams, public support for the conflict had evaporated.

The 1970s saw yet another massive drawdown with the military falling from 3.5 million strong in 1969 to 2 million in 1979. Along the way the draft ended and the era of the all-volunteer forces began. Drug use, racial tensions, insubordination, even “fragging” (soldiers attacking their officers) were hallmarks of this era, which culminated in a hollow army that could not deter the Soviet Union from invading Afghanistan or rescue the American hostages in Iran.

The Reagan defense buildup of the 1980s, which actually began under Carter, rescued the military from the doldrums of the 1970s and created the force that won the Gulf War in such spectacular and unexpected fashion. This military also helped apply the pressure needed for the final collapse of the Soviet Union.

But then after Desert Storm and the end of the Cold War, the George H.W. Bush and Clinton administrations rushed to spend the “peace dividend.” The military shrank from 2.1 million active-duty personnel in 1989 to 1.3 million in 1999. The Army was particularly hard hit: It shrank from 769,000 to 479,000 soldiers.

The “end of history” reverie ended in 2001, but, even after 9/11, the Army was too small to fight in both Iraq and Afghanistan. We are still paying a price for not sending enough troops to pacify both countries after we toppled their previous regimes. Partly this was a matter of miscalculation on the part of Bush administration officials who thought that American troops would do more harm than good. But that calculation itself was driven by the paucity of available troops.

After our early failures in Iraq, President Bush belatedly expanded the size of the Army and Marine Corps—although not enough to make up for the post–Cold War cuts. (The Army today has 200,000 fewer active-duty troops than in 1991.) Emergency appropriations also provided hundreds of billions of dollars to fund the wars, enabling the purchase of thousands of new armored vehicles, unmanned aircraft, and other important enablers. But there was never enough money to make up for the procurement holiday of the 1990s.

We are still suffering the consequences of the post–Cold War drawdown. The Navy, down from 546 ships in 1990 to 284 today (the lowest level since 1930), is finding it hard to fight Somali pirates, police the Persian Gulf, and deter Chinese expansion in the Western Pacific. The Army and Marine Corps are forced to maintain a punishing operational tempo that drives out too many bright young officers and non-commissioned officers. The Air Force, which has been reduced from 82 fighter squadrons in 1990 to 39 today, has to fly decades-old aircraft until they collapse. The average age of our tanker aircraft is 47 years, of strategic bombers 34 years, and some older fighter aircraft are literally falling out of the sky.

The bipartisan Quadrennial Defense Review Independent Panel led by Stephen Hadley and William Perry found last year “a growing gap between our interests and our military capability to protect those interests in the face of a complex and challenging security environment.” The panel further noted:

There is increased operational tempo for a force that is much smaller than it was during the years of the Cold War. In addition, the age of major military systems has increased within all the services, and that age has been magnified by wear and tear through intensified use….The Department of Defense now faces the urgent need to recapitalize large parts of the force. Although this is a long-standing problem, we believe the Department needs to come to grips with this requirement. The general trend has been to replace more with fewer more-capable systems. We are concerned that, beyond a certain point, quality cannot substitute for quantity.

The Hadley-Perry commission recommended that “as the force modernizes, we will need to replace inventory on at least a one-for-one basis, with an upward adjustment in the number of naval vessels and certain air and space assets.” It also recommended maintaining the size of our current ground forces because “the increased capability of our ground forces has not reduced the need for boots on the ground in combat zones.”

Both of those recommendations are absolutely on the mark. And both are increasingly difficult to carry out given the magnitude of defense cuts already agreed upon. They will become an utter impossibility if sequestration occurs.

According to the majority staff of the House Armed Services Committee, this is what could happen after sequestration: the Army fall from 569,000 active-duty soldiers today to 426,000; the Marine Corps from 202,000 to 145,000; the Navy from 284 ships to 238; the Air Force from 1,990 fighter aircraft to 1,512 and from 135 bombers to 101. Even if the full impact of sequestration is not felt, the consequences for our military readiness will still be dire.

Those who argue in favor of cuts point out that defense spending has doubled in real terms since 9/11. That is true, but much of the spending has gone to current operations, personnel costs, ballooning health-care costs, and other necessities. It has not been used to recapitalize our aging inventory of weapons systems or to expand a ground force cut by a third since the Cold War.

Instead, even as we continue to fight in Afghanistan and Iraq, the Defense Department has been eliminating or reducing one system after another. Before his retirement last summer, Defense Secretary Robert Gates cancelled or capped 30 procurement programs that, if taken to completion, would have cost more than $300 billion. The cancellations included the Army’s Future Combat System, the Marines’ Expeditionary Fighting Vehicle, the VH-71 presidential helicopter, the Navy’s CG(X) next-generation cruiser, the Air Force’s F-22 fighter and C-17 cargo plane, and the Airborne Laser. Other programs, such as the Navy’s new aircraft carrier, were delayed, while the number of F-35 fighters, Littoral Combat Ships, and other systems planned to be purchased was reduced.

It’s not only weapons systems we’re losing. It’s personnel. Gates closed headquarters, eliminated general-officer slots, and even shut down the whole U.S. Joint Forces Command. He announced that he was whittling down Army and Marine end-strength by 47,000 personnel, reversing the increase in the size of the ground force that he had pushed through to deal with the wars in Afghanistan and Iraq. Further cuts in end-strength are undoubtedly coming as a result of greater budget cuts, thus throwing out of work—at a time of already high unemployment—tens of thousands of men and women who have signed up to serve their country.

That may make sense if you assume we will have no need for large numbers of ground combat forces in the future, but as Gates himself said earlier this year: “When it comes to predicting the nature and location of our next military engagements, since Vietnam, our record has been perfect. We have never once gotten it right, from the Mayaguez to Grenada, Panama, Somalia, the Balkans, Haiti, Kuwait, Iraq, and more—we had no idea a year before any of these missions that we would be so engaged.” Because the world is such an uncertain, dangerous place, we need the deterrence and flexibility provided by a large ground force. But maintaining soldiers in an all-volunteer force is expensive, and it is almost a certainty that they will be sacrificed to achieve arbitrary budget targets.

What strategy are we following here? Is there any strategy at all? None is apparent from the outside—or, from what people at the Pentagon tell me, from the inside. It has been said that this is a budget in search of a strategy, but we will be hard put to it to achieve all, or even most, of our strategic objectives with a third less resources.

The Hadley-Perry commission identified four enduring security interests for the United States: “The defense of the American homeland; assured access to the sea, air, space, and cyberspace; the preservation of a favorable balance of power across Eurasia that prevents authoritarian domination of that region; providing for the global common good through such actions as humanitarian aid, development assistance, and disaster relief.” None of those interests will change, no matter what budget decisions are made in Washington; all that will change will be our ability to defend those interests.

Certainly there has not been—nor is there likely to be—a decreased demand for the armed forces. They are constantly having new missions thrown their way, from defending our nation’s computer networks to deposing a dictator in Libya and providing relief to Japanese tsunami survivors. Those who call for austerity in our defense budget do not suggest which missions, which specific operations, they will willingly forego. And when they do, the suggestions are usually insufficient to achieve serious savings.

I am not by any stretch of the imagination claiming that every penny of defense spending is sacrosanct. It is impossible to deny that there is waste, fraud, and abuse in the defense budget. The problem is that there is no line item for waste, fraud, and abuse, and hence no way to pare only wasteful spending. Indeed it is hard to agree about what constitutes wasteful spending, because every defense program has its passionate defenders, especially on Capitol Hill, and it is possible to make compelling arguments in favor of them all.

At the end of the day, less money results in less capability. And less capability is something we cannot afford at a time when we face a rising China, a nuclear North Korea, an Iran on the verge of going nuclear, a Pakistan threatened as never before by jihadists, and numerous terrorist groups, ranging from the Afghan and Pakistani Taliban to the Shabab in Somalia and al-Qaeda in the Arabian Peninsula. These groups threaten not only vital U.S. interests abroad but also increasingly the American homeland itself, as evidenced by AQAP’s attempt to mail parcel bombs to the U.S. and by the Pakistani Taliban’s sponsorship of an attempt to set off a car bomb in Times Square.

China presents a particularly worrisome long-term problem. It is in the midst of a rapid defense buildup which has allowed it to field a stealth fighter, an aircraft carrier, diesel submarines, cyberweapons, “carrier-killer” and satellite-killer ballistic missiles, and numerous other missiles. Even as things stand, China is increasingly able to contest the U.S. Navy’s freedom of movement in the Western Pacific. As long ago as 2008, Rand predicted that by 2020 the U.S. would not be able to defend Taiwan from a Chinese attack, and that was before the surprise unveiling of China’s J-20 Stealth fighter or its new aircraft carrier. The timeline for American dominance being threatened is shortening. The safety of U.S. bases in Okinawa, Guam, and elsewhere in the region can no longer be assured, creating the potential for a 21st-century Pearl Harbor. That trend will be exacerbated—leading to a potentially dangerous shift in the balance of power—unless we build up our shrinking fleet. But given the budget cuts being discussed, we will have trouble maintaining the current size of our fleet, much less expanding it.

We have already cancelled the F-22 and cut back the procurement of the F-35. Is the F-35 to be cancelled altogether or cut back to such an extent that we will have no answer to the fifth-generation fighters emanating from Russia and China? If that were to come to pass, it would signal the death knell for American power in the Pacific. If our power wanes, our allies will have to do what they need to do to ensure their own security. It’s easy to imagine, under such a scenario, states such as Japan, South Korea, and Taiwan acquiring their own nuclear weapons, thus setting off a dangerous and destabilizing nuclear arms race with China.

Even given the dire consequences, it might still make sense to cut the defense budget—if it were bankrupting us and undermining our economic well-being, which is the foundation of our national security. But that’s not the case. Defense spending, including supplemental appropriations, is less than 5 percent of gross domestic product and less than 20 percent of the federal budget. Both figures are lower than the historic norm. That means our armed forces are much less costly in relative terms than they were throughout much of the 20th century. Even at roughly $550 billion, our core defense budget is eminently affordable. It is, in fact, a bargain, considering the historic consequences of letting our guard down.

The United States’ armed forces have been the greatest force for good the world has seen during the past century. They defeated Nazism and Japanese imperialism, deterred and defeated Communism, and stopped numerous lesser evils—from Slobodan Milosevic’s ethnic cleansing to the oppression perpetrated by Saddam Hussein in Iraq and the Taliban in Afghanistan. Imagine a world in which America is not the leading military power. It would be a brutal, Hobbesian place in which aggressors rule and the rule of law is trampled on. And yet Congress will be helping to usher in such a New World Disorder if it continues to slash defense spending at the currently contemplated rate—just as previous Congresses did with previous rounds of “postwar” budget cuts going back to the dawn of the Republic.

But there is nothing inevitable about the outcome. The first tranche of sequestration cuts is not scheduled to take effect until the 2013 fiscal year. That means Congress has most of 2012 to find an alternative. Unfortunately, President Obama has threatened to veto any bill that tries to exempt the defense budget from sequestration. But that should not prevent pro-defense Democrats and Republicans from pushing such a bill anyway. If even one year of sequestration were to occur, major weapons systems (which will be costly and difficult to restart) might be cancelled—and great numbers of veterans (whose experience would be lost forever) might be layed off.

In the long run, the question of whether or not—and to what extent—we will cut defense will be decided in the 2012 elections. Obama appears sanguine about the impact of defense cuts, but his Republican challengers are not. Mitt Romney has promised to protect the defense budget and expand naval shipbuilding. Rick Perry has called on Leon Panetta to resign rather than accept massive cuts. Even Newt Gingrich, who has been critical of wasteful Pentagon spending, has said that sequestration would be “totally destructive” and “very dangerous to the survival of the country.”

It is commonly said that every election is a turning point in our history. In many cases that’s nothing more than partisan hype. In the case of the 2012 election, it’s true: The future of the U.S. armed forces, and of American power in general, could depend greatly on the outcome.