Our current historical moment may signal the unraveling of the post-1945 world order, according to researchers from UC Berkeley and Columbia University. Recent shifts in U.S. governance have had rippling consequences for global equilibrium, they argue in a newly published paper, putting international law and institutional legitimacy at risk.
In the aftermath of World War II, the post-1945, or liberal, world order established a framework for peace, sovereignty and stability. At its core was a shared commitment to preventing another world war. The U.S. played a leading role in building and sustaining this system.
In “The Unconstrained Future of World Order: The Assault on Democratic Constraint and Implications for US Global Leadership,” published in International Organization, UC Berkeley Political Science Professor Susan Hyde and Columbia Political Science Professor Elizabeth Saunders argue that the U.S., which helped construct the post-1945 world order, is now fracturing it. They examine how these changes might reshape the future of U.S. global leadership.
“The United States’ willingness and capacity to continue as the underwriter of international order and global governance is now very much in doubt because the U.S. presidency is now essentially unconstrained in the international realm,” Hyde said.
In their paper, Hyde and Saunders argue that the postwar system depended not just on U.S. power, but also on limits to how that power could be used. Those constraints helped sustain international cooperation by making U.S. actions more predictable, the research shows. However, as those constraints weaken, the system that relied on them is becoming less stable.
“Trump has taken steps that many scholars argue have already amounted to a change in regime,” said Hyde. “Even if the United States remains a democracy, long-term forces and Trump’s short-term assault on domestic constraints have already removed what limited checks remained on U.S. foreign and security policy.”
These changes, they noted, are rooted in broader shifts within American politics. Hyde and Saunders argue that a divided media landscape, growing political polarization and a changing global security environment have made it easier for leaders to take action without oversight. These factors have damaged the checks and balances that once guided U.S. foreign policy, they said.
“The United States remains the most militarily powerful state, and how it chooses to use that power will dramatically affect international relations, for better and for worse,” said Hyde.
As these constraints erode, the U.S. may find it harder to sustain the economic and political commitments that underpin global leadership, they said. Building coalitions, funding international initiatives and maintaining trust among allies all depend on a level of domestic stability that is increasingly uncertain, they explained.
“American leaders have stretched domestic constraints beyond recognition, such that it is no longer strong enough to bind the global order,” Hyde said.
The result may be a more unstable and fragmented international system, their research shows. Without a constrained and reliable United States to uphold it, the post-1945 world order may soon give way to a new and more unpredictable global order, the researchers said.