Debating American Engagement: The Future of U.S. Grand Strategy

To the Editors (Campbell Craig writes)

In making their case for maintaining the United States’ policy of “deep engagement,” Stephen Brooks, John Ikenberry, and William Wohlforth stress that the U.S. security commitment to states in Europe, the Middle East, and East Asia, together with the formidable specter of American preponderance, stifles regional rivalries and hinders the resurgence of a dangerous era of multipolar power politics. The authors contend that a policy of U.S. retrenchment could spark the “return of insecurity and conflict among Eurasian powers,” whereas a continuing policy of deep engagement, by “supplying reassurance, deterrence, and active management … lowers security competition in the world’s key regions, thereby preventing the emergence of a hothouse atmosphere for growing new military capabilities.”¹ In short, they suggest, deep engagement reduces the chances of a major Eurasian war; a new strategy of retrenchment would increase them.

Brooks, Ikenberry, and Wohlforth do not acknowledge the possibility that a lack of conventional security competition among large Eurasian states, as well as their disinclination to balance against U.S. preponderance by traditional means,² might be explained by the simpler fact that nuclear weapons make such activity both prohibitively dangerous and strategically unnecessary.³ Perhaps would-be great powers in Eurasia would launch belligerent campaigns of expansion upon an American retreat to the Western Hemisphere, but they would have to weigh such policies against the reality that a regional war would quickly run the risk of an apocalyptic nuclear exchange. Britain, China, France, Israel, and Russia, after all, possess large nuclear arsenals, and it is impossible to imagine a war in which they would not use them if it came down to that or surrendering to a conquering aggressor. Under such conditions, nations do not envision waging protracted wars of grand territorial conquest.⁴ We are not in 1940 anymore.

Perhaps even more important, nuclear weapons provide states with the kind of protection that even the most formidable conventional forces could not offer before the nuclear era. If the specter of nuclear war dissuades nations from launching wars of conquest, then it also allows those in possession of substantial arsenals to threaten any foe considering an attack with nuclear retaliation. A putative superpower such as China knows that as long as its nuclear arsenal is invulnerable, it can avoid the military conquest of its territory.⁵ For what nation, no matter how rapacious, would try to conquer it if there were a good chance that it would suffer the immediate destruction of five or ten of its largest cities, much less total nuclear retaliation?⁶ Nations have engaged in balancing behavior for many reasons, but the core purpose has always been to accumulate sufficient power to avoid violent subjugation at the hands of their rivals.⁷ Because a secure retaliatory nuclear arsenal provides a uniquely efficient solution to that problem, nations such as China do not have to preoccupy themselves with the military capabilities and shifting allegiances of major rivals in the way that, say, Britain had to do around the turn of the twentieth century.

By making the prospect of major war apocalyptic, and at the same time giving regional powers an unprecedented ability to deter wholesale military invasion, nuclear weapons account for the absence of both security competition in dangerous regions of the world and attempts to balance against U.S. preponderance in a remarkably parsimonious fashion. This nuclear factor suggests that these regional powers are unlikely to initiate a major war in the foreseeable future regardless of whether the United States maintains its deep engagement or adopts a policy of retrenchment. The avoidance of general war between India and Pakistan, in a region where the United States plays a less preponderant role, would seem to bolster this claim.⁸

The geopolitical stasis created by nuclear weapons does not make the debate between advocates of deep engagement and retrenchment unimportant, however. While nuclear weapons make it unlikely that...