The changing fiscal and strategic realities led the Pentagon in 2018 to abandon the old two-war standard and to concentrate on China as the pacing threat. In practical terms, this means that, for the foreseeable future, the U.S. military will prioritize planning and resources for war in the western Pacific rather than Europe or the Middle East. This is not just a rhetorical shift; it means that the Pentagon will make fewer of the kinds of weapons used for land warfare or counterinsurgency and more of those used for aerospace and naval warfare, and less money and people for U.S. military commands in Europe and the Middle East to support United States Indo-Pacific Command. It also presumably means that, as Elbridge Colby has pointed out, even in the event that Russia moved first—say, against a Baltic state—the Pentagon would see a very powerful reason to reserve the bulk of its fighting strength for countering an opportunistic move by China in the western Pacific. 

If America possesses a military that is geared for war with one but not the other of its two great-power rivals, then America will have to rely on something other than only or primarily the U.S. military to cover its liabilities in what, by default, becomes the secondary theater: Europe. In that theater, it can be reasonably assumed that the United States will continue to maintain forces, but that these will be less and less adequate for deterrence or defeating Russia in a regional conflict. The job of diplomacy is to help cover these liabilities by bringing about international political configurations that better align finite American military and economic power with the primary threat. It can do so in two basic ways, which are not mutually exclusive. 

One is to build and operate effective coalitions of allies and partners in one or both regions for taking on more of the military burden vis-à-vis the two threats. Since the United States possesses extensive allies and partners in both regions, this becomes mainly about getting better value out of those relationships. Such an effort has been underway for several years and will inevitably continue. Successive administrations have sought to increase burden-sharing among allies and partners in both Europe and Asia. The tactics can be debated (Barack Obama used charm and shaming, Donald Trump used pressure, often to better effect; both pursued the same end) but recent experience suggests that, for the foreseeable future, allies may not take on the scale of defense burden that would be needed to significantly offset the U.S. military burden in their neighborhood vis-à-vis Russia and China. 

THE OTHER way diplomacy can help manage the gap between military resources and threats is by rendering one of the major rivals less threatening—in particular, by sequencing. While unfamiliar terrain for the post-Cold War United States, using diplomacy to sequence threats has in fact been the preferred method of averting two-front wars for great powers throughout history. The strategy has taken many forms, but generally boils down to three options. 

Option 1: “Flip” the weaker. Perhaps the most common form of sequencing is to align with the weaker of two rivals in order to concentrate resources on the stronger. This is the method that Edwardian Britain used when it recruited Tsarist Russia—against which it had waged a decades-long cold war in Central Asia no less intense than our own—into an alliance against Imperial Germany.  

This option is the most familiar to Americans from what was, arguably, our only episode in big-league sequencing: President Richard M. Nixon’s China gambit. Whenever the China-Russia problem is raised, this strategy is invariably discussed, except with Russia now cast as the rival to be courted and “flipped” in order for the United States to concentrate on China. The appeal of this option is obvious: as the largest and most formidable of China’s landward neighbors, a friendly (to us)—or even unaligned Russia—would force China to divert attention from the coasts (and competition with the United States) to its land frontiers. Perhaps it is for this reason that successive administrations have attempted to ease tensions with Russia to support a shift of emphasis to the Indo-Pacific. 

The problem with this approach is that Russia does not need it. When Henry Kissinger approached China, Beijing needed the opening as much or more than the United States because it feared attack by the USSR. Similarly, when the British brokered the Anglo-Russian Convention of 1907, Russia had just suffered a devastating defeat by Japan and needed relief from the resulting intense military, budgetary, and domestic pressures. It shared with Britain the common and very compelling threat of Imperial Germany. And the two had something tangible (Persia, Afghanistan, and Tibet) to barter over as a means of cementing the deal. 

None of these conditions are present in U.S.-Russia relations today. Russia has not recently suffered a defeat or major setback; indeed, Vladimir Putin is riding high. Contrary to misconception, there is nothing tangible, at least as Russia would define it, over which the United States and Russia can constructively barter. Setting aside the moral considerations of say, a partition of Ukraine, any such understanding would lack enforceability and almost inevitably result in Moscow moving the geopolitical line of contact a few degrees of longitude to the west, to Poland or Romania. Were this to happen, the United States would likely find the pressure on the NDS’ intended secondary theater heightened rather than alleviated. 

Option 2: Defer competition with the stronger. A second sequencing strategy is to delay rivalry with the stronger of two opponents in order to deal conclusively with the weaker. The mid-sixteenth-century Republic of Venice employed such a strategy to deflect the threat of the rising Ottoman Empire and deal conclusively with its mainland rival Milan. A similar logic guided Britain’s ill-fated quest in the 1930s to appease Germany in order to prioritize naval resources for the Far East and buy time for rearmament in Europe. 

In today’s context, a deferment strategy would require America to palliate disputes with China and avoid outright military collisions with Beijing in order to concentrate pressure on Russia, with a view to eventually shifting attention to China at a later date. Taken to its logical extension, this strategy would require at least a partial reconsideration of the NDS’ hyper concentration on China. If pursued on the historical pattern, it could potentially even entail an effort to enlist a “responsible stakeholder” China, at least tactically and temporarily, in the effort to isolate what is the more truculent Russia.  

The obvious problem with this option is that the window of opportunity it requires vis-à-vis China has probably already closed. The ideal time for such an approach would have been earlier in the previous decade, after Russia had already embarked upon its aggressive course but when China remained a nominally constructive player and the balance of power remained favorable to the United States. Since then, the U.S.-China dynamic has deteriorated in ways that make a prolonged period of tranquility in that relationship hard to imagine. Crucially, this is more and more because of the decision on Beijing’s part to relinquish a hide-and-bide posture and align closely with Moscow, and by its increasing material strength vis-à-vis the West. Against this backdrop, taking a softer U.S. line on, say, Taiwan, might encourage rather than deflect Chinese ambition while impairing Washington’s ability to recruit the regional coalitions upon which its long-term prospects in Asia ultimately rest. As the 1930s British example shows, the results of such a miscalculation could be catastrophic, potentially even hastening the advent of the two-front war that the strategy was intended to avoid. 

Option 3: Co-opt both rivals. The third and most difficult, but perhaps most elegant, solution for the simultaneity problem has been to transcend it entirely—to negate its pressures by co-opting both rivals into cooperative structures that prevent or mitigate conflict. This was the method that the nineteenth-century Austrian statesman Klemens von Metternich used to enmesh Austria’s flanking rivals, France and Russia, in a system of concert diplomacy that kept the peace in Europe for almost a century. 

The modern equivalent of Metternich’s strategy would be for America to use international institutions to engage China and Russia in the pursuit of win-win outcomes on shared global problems. That is what the Biden administration appears to have had in mind in its efforts to find common ground with Beijing and Moscow on “transnational” problems like climate change. 

Cooperation with geopolitical rivals can be beneficial when the resulting structures are built on stable power relationships and shared interests. But neither of these conditions are present in U.S. relations with China and Russia. Both powers maintain active revisionist claims, the fulfillment of which are, from their perspectives, a prerequisite to achieving their full potential as great powers. Both correctly see the underlying power relationships upon which current institutions rest as being in flux and, in China’s case, changing in their favor. For both, international institutions are a means by which to pursue power politics and constrain U.S. power. As such, U.S. efforts to jointly tackle, say, climate change, are attractive insofar as they entail self-damaging U.S. concessions with which China can feign compliance while waiting on the correlation of power to shift more decisively to Beijing’s advantage.