Second, international institutions and governance mechanisms will be thrown into further disarray as each side seeks to undermine those favored by or created by the other side. Key international governmental organizations, such as the United Nations, the IMF, the World Bank, and mechanisms such as the G20 could shatter into a patchwork of institutional battlefronts. China may well try harder to use the BRI to lock most of the Global South into a technological ecosystem closed to the high-tech products of Western economies, or exploit its market share to dictate foreign policy. The nascent but contentious effort to design a regime governing the flow and storage of data will likely entrench two competing models. In general, the expansive but ragged institutional framework that comprises today’s global governance structure will fracture into something resembling that during the original Cold War. Only this time, it will be a more balanced standoff.

Third, the global commons—its natural resources, communications links, and shared knowledge base—will increasingly be an arena of competition rather than cooperation. Any level of cooperation in managing these commons, necessary as it may be, will be measured against the advantage it may yield to the other side. The sharp descent into a deep U.S.-Russia cold war illustrates how rapidly and thoroughly all forms of educational, scientific, and technical cooperation can be scuttled. Obstacles to addressing existential threats, such as those posed by climate change and nuclear weapons, will swell.

Finally, bilateral competition between the United States and China, as in the original Cold War, will inflame and make less manageable regional conflicts in strategically significant parts of the world. The immediate and volatile case of Taiwan, rising tensions in the South China Sea, and the decades-old uncertainties on the Korean Peninsula will not be a U.S.-China cold war’s only arenas. It will spread across the globe, and as the struggle to secure interests in more distant critical regions intensifies, the familiar pattern of one or both powers intervening in local conflicts, backing opposing parties, and acting not as peacemakers, but as contestants, will exacerbate regional conflicts, as it did during the Cold War.

THUS, A U.S.-China cold war will transform the international political system in fundamental ways, but alone it is not likely to alter its current amorphous structure. Combined with the new U.S.-Russia cold war, however, it will once again give the system a bipolar structure. The force field created when the untamed animosity between Russia and the West merges with a comparable hostility between China and the United States will vastly shrink the room for maneuver of those struggling to stay above the confrontation. Even a major player like India—which has remained aloof from the U.S.-Russia cold war and exploited the Ukrainian crisis to buy Russian oil at discounted prices—will find its choices much diminished. The conjoined cold wars will inevitably produce a China-Russia axis—albeit with complications and limitations—thus, raising the China challenge for India and, with it, the need to give priority to India’s stake in U.S.-led counterbalancing efforts against China. Other countries, including substantial parts of the Global South, may try to play one side against the other and seek the economic rewards—but this path will be narrowed by the harsh conditionality the battling sides will attach to their favors.

The bipolarity of the original Cold War came apart as the result of five centrifugal forces: the Sino-Soviet split, polycentrism in the Communist world, the filling of power vacuums and the rise of powers like China and India, the Soviet Union’s faltering economy, and the overreach by both sides in the cases of Vietnam and Afghanistan. Except for potential overreach, the forces at work in a bipolar contest driven by dual cold wars will more likely be centripetal, as the political, economic, and security options open to much of the remainder of the world shrink.

The consequences of moving from the current level of great-power strategic rivalry to a new bipolarity driven by two interlocking cold wars will be immense and tragic. In present circumstances, there is again a growing normative bipolarity at the level of the countries’ internal political orders and value systems. However, the possibility, although shaken by Russia’s invasion of Ukraine, still exists that at the international level China and the United States could reconcile themselves to rules allowing for a modus vivendi.

When Putin argues that Peter the Great in the Great Northern War was not taking lands from Sweden, but returning to Russia what historically and legitimately belonged to it, as he is doing in Ukraine, he has thrown over the anchoring norm of the post-World War II UN system, and substituted its eighteenth-century Hobbesian opposite. If, as appears to be the case, a majority of countries tolerate the seizure of another country’s sovereign territory by force, the norm at the center of the contemporary international order is seriously endangered. Worse, if Xi embraces Putin’s defection, let alone views resolving the Taiwan issue as the decisive factor determining his personal legacy, as Putin does Ukraine, and then acts accordingly, any thought of finding common ground on the rules governing the international system vanishes.

China does not rule out the use of force if Taiwan moves toward independence, but it denies a readiness to force the issue by military means. For the moment, this leaves room for the two countries to seek, as former Australian prime minister Kevin Rudd suggests, a “managed strategic competition” with rules designed to prevent the two countries from lurching into war. His rules include both sides abstaining from cyberattacks against critical infrastructure, the United States “strictly adhering to the ‘one China’ policy,” China “dialing back ... provocative military exercises, deployments, and maneuvers,” and China ceasing further militarization of the South China Sea, reciprocated by a reduction of U.S. and allied operations in the area.

If, however, a new U.S.-China cold war merges with an inflamed U.S.-Russia cold war, then the quest for rules of the road such as Rudd suggests has no chance. The world will have returned to a state more destructive and dangerous than that in the period from the 1948 Berlin crisis through the 1962 Cuban Missile Crisis. It would be more destructive, in fact, because the current international system’s economic, technical, and social components and their nexuses are far more extensive and complex. Such a standoff would even be more dangerous than the original Cold War because two new cold wars will each contain the grounds for a major military conflict, even World War III, as the current Russo-Ukrainian War prompts Biden to warn.

MAYBE MAJOR economies are too entangled, globalized supply chains too essential, and data platforms too impervious to fracturing that U.S. and Chinese decoupling and weaponized economics can only go so far. Maybe the economic dynamism that gingers Xi Jinping’s ambitions is overhyped, and China's economic vulnerabilities are greater than commonly recognized. Maybe China will decide that its Russian partner is too reckless and inept to embrace too closely. And maybe U.S. allies and other key players will manage to stay free from the riptide of U.S.-China rivalry, or even from the bipolar force of two entwined cold wars, and create barriers to the damage either can cause. But a prudent regard for the tragic, unexpected turns history can take would urge leadership in Washington, Moscow, and Beijing to carefully weigh the trajectory they are on and how seriously they want to test moving in another direction.

That will not be easy or, alas, even likely. The future of what is now a ravaged U.S.-Russian relationship will be barren and riddled with dangers. The war in Ukraine will likely end with no agreed resolution and either with a substantial portion of Ukraine occupied and absorbed by Russia or in a Korean War-like stalemate. In either case, Russia will have lost Ukraine, NATO will have made Ukraine its security ward, and the EU, with Ukraine its imminent member, and NATO will face off with Russian military forces along an East European front from the Black Sea to the Arctic, including its new 830-mile Finnish extension.

Both Russia and the West will then have two choices. The natural inclination on both sides—already signaled at NATO’s July Madrid summit—will be to reconfigure their beefed up military forces and push a larger number of them forward to the line of contact. The alternative would be to focus an equal effort on restoring and strengthening the military guardrails dismantled over the course of the post-2014 U.S.-Russia cold war: to reconstitute a modernized version of the Treaty on Conventional Forces in Europe governing the numbers of forces and kinds of weapons forward deployed; to resuscitate the Open Skies Treaty and Vienna Document providing for transparency in military activity and limits on military maneuvers; to restore the NATO-Russia Council as a point of regular military-to-military contact; and to embrace the earlier tentative prospect of eschewing the deployment of intermediate-range nuclear weapons in the European theater.

Even sooner, by October 2022—the sixtieth anniversary of the Cuban Missile Crisis—whatever the state of the Russo-Ukrainian War, the two countries will still have nearly 90 percent of the world’s nuclear weapons in an increasingly complex and unstable nuclear world—and it is simply common sense, as the two presidents now seem ready to do, to return to their suspended “strategic stability dialogue.” Following the June 2021 summit, the dialogue produced two critical working groups—one on Principles and Objectives for Future Arms Control and the other on Capabilities and Actions with Strategic Effects. As the risks inherent in their deepening confrontation mount, exploring paths to nuclear arms limitations and stabilizing the nuclear relationship—the task of the first group—becomes ever more urgent. Doing so by considering emerging technologies, new war fronts (such as cyber and space), and concepts for nuclear use that threaten strategic stability in more complex ways—the task of the second group—becomes ever more essential.