02/07/2013 03:03 pm ET Updated Apr 09, 2013

Are We Really Pulling Out of Afghanistan?

America's long war in Afghanistan is drawing to a close. President Obama recently announced that he will speed up troop withdrawals and end most unilateral combat operations there. Yet history teaches that the end of combat rarely means all the troops come home.

In fact, since 1945 America's grand strategy has been built around troops deployed and based in former war zones. From Korea to Kuwait to Kosovo, U.S. military bases circle the globe.

Will Afghanistan be different? The Obama administration is currently weighing whether to keep American troops there beyond 2014. Many factors will go into this decision, but one is surprisingly critical to any continued deployment of troops: legal immunity. Immunity is so essential that without it, American troops will not remain in Afghanistan.

Indeed, the refusal of Iraq to grant continuing immunity to American troops led to a complete U.S. military withdrawal in 2011.

Why is immunity so important -- and often so controversial? To understand, step back and consider the broader U.S. approach to national security.

We enjoy many natural defensive advantages: vast oceans to the east and the west, friendly neighbors to the north and the south. Yet the federal government has long pursued an outward-looking approach to security that relies on the extensive -- and expensive -- projection of power.

Since 1945, a strategy of forward deployment via foreign bases has been critical to U.S. defense, and in turn to our global leadership. Overseas bases existed before 1945 -- think of Guantanamo Bay, where the U.S. has maintained a "coaling and naval station" for over a century -- but the number and scale of these bases grew dramatically during the Cold War. Little changed with the end of the Cold War, however; in fact, many new bases came into existence. Today, there are some 500 foreign bases in nearly 40 nations.

This heavy presence overseas has drawn fire from right and left alike: both Noam Chomsky and Ron Paul have criticized our extensive foreign basing strategy. But overseas troops remain central to the exercise of American power and, many have argued, have been the basis of lasting peace in Europe and at least stable relations in Asia. A key issue for the future of Afghanistan is whether it, too, will remain home to a large numbers of American troops.

But troops don't just set up camp in foreign countries and stay awhile. Typically, American troops based abroad are governed by what is called a "Status of Forces Agreement," or SOFA for short. The U.S. has negotiated over 100 SOFAs. SOFAs are agreements between the U.S. and the host country that specify what laws govern the troops and who has legal jurisdiction over various issues.

American troops based in abroad, for example, don't arrive on a tourist visa, so special rules have to be made to govern their entry (and often their families') into the country. Likewise, SOFAs address a wide array of mundane but significant issues, such as taxation.

The real meat of a SOFA, however, is in the realm of criminal law. Most American SOFAs declare that the U.S. has jurisdiction over many offenses. This means that for many criminal and civil matters, an American who breaks the law in, say, Germany cannot be tried in a German court -- though American troops may face U.S. military justice or, if a civilian dependent is the accused, may conceivably be sent home for trial (which, to the chagrin of host states, doesn't always happen.)

The rationales for this arrangement vary, but include that our troops need protection from alien and unfamiliar legal systems; that military discipline requires military justice; and, maybe most importantly, that as a practical matter American politicians don't want to put our troops at risk of foreign prosecution and punishment.

This kind of immunity bears a family resemblance to the more familiar immunity enjoyed by diplomats. Diplomatic immunity shields ambassadors from local prosecutions on the theory that they could not effectively do their jobs if they could be jailed by their hosts.

For the most part immunity is a quiet practice that allows the wheels of diplomacy to turn. But diplomatic immunity also allowed Raymond Davis, the CIA contractor who in 2011 gunned down two Pakistanis on the streets of Lahore, to escape prosecution for murder. (The U.S. maintained he was properly listed as an accredited diplomat, and, after jailing Davis for some time, the Pakistanis relented).

So even diplomatic immunity is not without controversy. And immunity for military servicemembers is no different. In Japan, for example, incidents ranging from rapes to manslaughter have led to many protests against the arrangement. In some parts of Japan, the special legal rights of American servicemembers have become an important domestic political issue.

There is at least one major difference between diplomatic and military immunity, however. Diplomatic immunity is reciprocal. One reason we are careful to respect the legal rights of foreign diplomats is because we have so many of our own diplomats posted abroad. That risk of tit-for-tat prosecution (or worse) helps to maintain the legitimacy of the system.

Military immunity, by contrast, is not reciprocal. Germans -- or Afghans -- do not have military bases in Arizona or Ohio. SOFAs are inherently unequal arrangements. And this makes the negotiation of a SOFA for American troops complicated. The host nation may see it as an infringement on their sovereignty, and local populations may resent the special treatment American troops receive.

SOFAs can remind other nations, especially in the Middle East, of their subjugation by the West in the 19th century, when Westerners were often granted "extraterritorial rights" that gave them immunity from local laws and allowed them to follow the law of their home country. Like SOFAs, these treaties were clearly unequal and are today often remembered as humiliations. (See China.)

The unhappy history helps explain why the U.S. and Iraq failed to negotiate a SOFA in 2011 that would have allowed a continued presence of American troops. The Iraqi leadership feared that granting American troops immunity would be deeply unpopular. Immunity was seen as a imperialistic and demeaning. Iraqi opposition was especially vehement given events like the mass shooting in Nisour Square in 2007, in which American contractors killed 17 Iraqis. The contractors faced no prosecution thanks to a sweeping grant of immunity that had earlier been decreed by the "Coalition Provisional Authority" in Iraq.

For many Iraqis, in short, immunity was akin to subjugation and semi-sovereignty. Yet for the U.S., immunity was a nonnegotiable requirement. The result -- not necessarily a bad one, but one certainly fraught with major implications -- has been no lasting American military presence in Iraq.

Will the same happen in Afghanistan? Certainly Hamid Karzai's government shares many of the concerns that motivated Iraq. Special rights for foreigners are never popular. Yet a continued U.S. presence also has significant appeal in Afghanistan; history has shown that American troops can be a powerful force for stability.

The Obama administration will surely reduce the number of American troops in Afghanistan substantially. The key question is how far and whether the right number of troops -- or, if immunity is not granted, the only number -- is zero. For his part, Karzai recently stated that "granting immunity to American soldiers is not a decision that could be made by Afghan government... This is a decision that should be made by the Afghan people in a Loya Jirga: whether they are granting immunity to them or not; if yes, how and under what conditions." We will soon see what the appetite of Afghanis is for immunity -- and by extension, what the future of the U.S.-Afghan relationship is.

Either way, America's long war -- 12 years and counting -- is coming to an end. And while war is politics by other means, it's often law that determines the nature of the peace.