Although the wars in Afghanistan and Iraq are far from the costliest the United States has ever fought in terms of either blood or treasure, they have exacted a much greater toll than the relatively bloodless wars Americans had gotten used to fighting in the 1990s. As of this writing, 2,344 U.S. troops have been killed in Afghanistan and 4,486 in Iraq, and tens of thousands more have been injured. The financial costs reach into the trillions of dollars.
Yet despite this investment, the returns look meager. Sunni extremists from the Islamic State of Iraq and al-Sham (ISIS), also known as the Islamic State, and Shiite extremists beholden to Iran have divided the non-Kurdish parts of Iraq between them. Meanwhile, the Taliban and the Haqqani network remain on the offensive in Afghanistan. Given how poorly things have turned out, it would be tempting to conclude that the United States should simply swear off such irregular conflicts for good.
If only a nation as powerful and vulnerable as the United States had the option of defining exactly which types of wars it wages. Reality, alas, seldom cooperates. Over the centuries, U.S. presidents of all political persuasions have found it necessary to send troops to fight adversaries ranging from the Barbary pirates to Filipino insurrectos to Haitian cacos to Vietnamese communists to Somali warlords to Serbian death squads to Taliban guerrillas to al Qaeda terrorists. Unlike traditional armies, these enemies seldom met U.S. forces in the open, which meant that they could not be defeated quickly. To beat such shadowy foes, American troops had to undertake the time-intensive, difficult work of what’s now known as counterinsurgency, counterterrorism, and nation building.
There is little reason to think the future will prove any different, since conflict within states continues to break out far more frequently than conflict among states. Although the world has not seen a purely conventional war since the Russian invasion of Georgia in 2008, more than 30 countries -- including Colombia, Iraq,