Harold Hongju Koh—
If re-elected, could President Trump, by a single tweet, withdraw America from the United Nations, NATO, and every treaty and international organization to which the U.S. belongs? Or if re-elected, could President Biden gradually take us to war throughout the Mideast—Gaza, Yemen, Iran, the Red Sea—by supplying weapons and ordering drone strikes, cybercommands and Special Forces without congressional approval?
Commonsense might answer “No,” but in reality, we can’t be sure. Every school child knows that America is governed by a constitutional system of separation of powers and checks and balances, where the President proposes, Congress disposes, and the courts say what the law is. But in foreign affairs, that’s not true and never has been. Our Constitution has not worked that way when national security is on the line. As America has grown more globally powerful, a different institutional dynamic has arisen, whereby the President acts, Congress defers, and the courts decline to rule or rule for the President. Over the last fifty years, the synergy among these institutional incentives has led to a startling accretion of presidential power, and explosive growth of executive and American unilateralism in national security affairs: witness Vietnam, Iran-Contra, 9/11, and the two impeachments of Donald Trump.
This increasing imbalance of foreign affairs power has intensified across recent administrations of both parties. Some presidents like Trump and George W. Bush proactively grabbed unilateral power, while others (Clinton, Obama, Biden) reactively asserted unilateral authority when they could not win congressional support. This shift towards extreme imbalance spiked sharply during Donald Trump’s tumultuous presidency. Trump ordered a discriminatory “Muslim Ban,” unilateral exits from treaties and agreements, defied Congress’ power of the purse by building a border wall over its objection, lethally targeted an Iranian general on Iraqi soil, and politicized the Justice Department to punish political “enemies.” His two impeachments illustrated how far he had diverted foreign policy to partisan political ends. The Mueller Report documented how he welcomed Russian interference in the 2016 presidential election and strongarmed Ukraine’s President Zelenskyy to get dirt on his 2020 political rival. Even after Trump was defeated at the polls, he encouraged mob violence to overturn the 2020 election results.
Through it all, Trump frustrated congressional oversight by asserting executive privilege and immunity and fighting subpoenas endlessly through the courts. He obstructed investigations, covered up offenses and attacked investigators and the media. And when his administration’s abuses triggered criminal investigations for violating national security laws, Trump pardoned the suspects or granted them clemency, even before trial. Even after leaving office, he endangered national security by continuing to hoard highly classified information at his private home.
Trump showed no remorse, instead claiming that all of his actions were authorized, justified by, and immunized from inter-branch interference by his plenary constitutional authorities. Under his extreme constitutional theory, any restraints coming from within the executive branch could be ignored under a theory of “unitary executive,” while any restraints coming from outside the executive could be treated as unconstitutional intrusions upon the President’s plenary national security powers. And candid interviews Trump has given during the 2024 presidential campaign vividly expose his intent to launch an even more monolithic imperial presidency on Day One that would nullify the rule of law for his second administration.
This constitutional challenge will not evaporate even if Joe Biden is re-elected. In the 21st century, new unprecedented threats—Ukraine, the Mideast, climate change, pandemics, cyberwarfare, and artificial intelligence—have provided even greater institutional incentives for Presidents both weak and strong to monopolize the foreign policy response; for Congress to acquiesce; and for courts to defer or rubber stamp, intensifying the interactive institutional dysfunction and disrupting the constitutional norm that national security policymaking should be a power shared.
Historically, Americans have asked the President to protect us from national security threats. But what should we now do if and when the President himself becomes a national security threat?
When these historical episodes occur, America’s persistent political response has been to normalize these aberrations and undercorrect. We consistently act as if the problem is personal, not structural. We see the solution as “throwing the rascals out,” even if those same rascals can return and repeat the historical pattern. Even if Trump is defeated in 2024, the problem will not disappear. Trump is far from the most unilateralist president imaginable: his own incompetence stymied many of his first-term initiatives and he had little taste for launching foreign wars. Nor is the simple answer “more democracy.” Democracy cannot check autocracy when autocrats invoke populist values or mob violence to steal elections. So whatever happens this November, greater constitutional disaster still remains just one election away.
Can we slow the dangerous march toward extreme executive unilateralism in foreign affairs? Thirty-five years ago, I took my first crack at that question, writing about Reagan’s Iran-Contra Affair. Having gained historical and practical perspective by serving in four presidential administrations of both parties over five decades, I have now substantially rewritten that book and updated it to today: stepping back to think deeply about this constitutional crisis, and how to fix it.
The National Security Constitution in the 21st Century argues that since the beginning of the Republic, a “National Security Constitution” has evolved within our constitutional law. That body of law promotes shared powers and balanced institutional participation in foreign policymaking. Today it is under attack from a competing claim of executive unilateralism generated by recurrent patterns of presidential activism, congressional passivity, and judicial tolerance. This dynamic has pushed presidents of both parties to press the limits of law in foreign affairs. Reviewing American history from the Republic’s beginning to the twenty-first century, I explain why modern national security threats have given presidents of both parties incentives to monopolize foreign policy decision-making, Congress incentives to defer, and the courts reasons to rubber-stamp. Even in the face of our current political dysfunction, my book suggests a workable strategy to address the growing imbalance of institutional powers in American foreign affairs and national security policy.
It is well past time to recognize the constitutional crisis that is upon us. If we don’t reform, our only alternatives are acceptance or despair. But if we can muster the vision and the will, there are crucial steps that politicians, lawyers, political scientists, and civil society can and must take. Only then can we restore the balance of our constitutional order and better address this century’s evolving global crises.
Harold Hongju Koh is Sterling Professor of International Law and former Dean at Yale Law School, where he has taught since 1985. After clerking for Supreme Court Justice Harry A. Blackmun and working for the Reagan Justice Department, he served in the Clinton Administration as Assistant Secretary of State for Democracy, Human Rights and Labor and as Legal Adviser and Senior Advisor at the State Department during the Obama and Biden Administrations. The recipient of 18 honorary degrees and dozens of human rights awards, he has testified regularly before Congress and litigated before many international and domestic courts, most recently for Ukraine against Russia in its suits before the International Court of Justice. A member of the American Philosophical Society, the American Academy of Arts and Sciences, and the Council of the American Law Institute—where he co-chairs the Restatement (Fourth) of Foreign Relations Law of the U.S.—he has been honored by Columbia and Duke Law Schools and the American Bar Association’s International Law Section for his lifetime achievements in international law. He is the author of 250 articles and nine books, including The National Security Constitution: Sharing Power After the Iran Contra Affair, which was awarded the Richard E. Neustadt Award by the American Political Science Association.
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