After 13 years of war, the loss of many thousands of lives, and the expenditure of trillions of dollars, what has the United States learned? The answer depends on not only who is asking but when. The story of the Iraq war would have different endings, and morals, if told in 2003, 2006, 2011, or 2014, and it will continue to evolve. As for Afghanistan, the narrative there has also shifted over time, and the ending also remains in doubt. Neither disaster has been unmitigated. But few would argue that Washington’s approach to either has been a success worth emulating. So the most important question today is what can be learned from the failures.

Two of our authors, Max Boot and Richard Betts, offer starkly different answers. Boot argues that even though Washington is fed up with counterinsurgencies, it will still end up waging more of them down the road, and so should focus on learning how to fight them better. Betts, by contrast, thinks Washington should go in the opposite direction: fighting fewer and more traditional wars and avoiding getting entangled in the domestic politics of chaotic countries on the strategic periphery. 

Rick Brennan, for his part, argues that even the best planning is worthless if not ably executed and updated as conditions change. Iraq’s current turmoil, he writes, is the predictable result of the United States’ premature exit, and he worries that a similar fate awaits Afghanistan.

As the world grapples with the medieval brutality of the Islamic State of Iraq and al-Sham, or isis, meanwhile, many in the United States and Europe have begun panicking at the thought that battle-hardened Western-born jihadists may return to unleash havoc at home. Daniel Byman and Jeremy Shapiro argue that such fears are overblown: as the last decade has shown, the threat of such blowback is often overhyped. Returning jihadists do pose dangers, they explain, but familiar and manageable ones.

Rounding out our package, Peter Tomsen assesses a new crop of books on the war in Afghanistan. These works help explain why, despite all of the West’s efforts, that country’s future remains up for grabs, and Tomsen, like Brennan, worries that Afghanistan could slide back into full-scale civil war unless it gets serious and sustained help from Washington.

Embarking on the campaigns in Afghanistan and Iraq more than a decade ago, U.S. officials basked in their power and brimmed with self-confidence. They never dreamed that, all these years later, their humbled successors would still be grappling with the same basic questions of whether and how to secure and stabilize those lands. We can only hope that current and future policymakers can learn from the mistakes and leave a better legacy.

—Gideon Rose and Jonathan Tepperman