The Law of War

I am not a law of war expert. I don’t play one on TV. But I wanted to share some basic principles and offer some suggestions for further reading as we watch the news unfold in Iran. The White House hasn’t offered the public a reason for the attack on Iran that would make it legal, and CNN is reporting they haven’t provided a “full accounting” to members of Congress either. This afternoon, Jake Sherman at Punchbowl News reported that “A senior Trump administration official said that U.S. intelligence ‘had indicators’ that the Iranians were going to use their missiles ‘preemptively, but if not, simultaneous’ to any American action on Iran.”

But if the real reason for our attack was warding off casualties from an Iranian first strike, you would have expected to hear the White House using that explanation from the start, which they didn’t. And now that we have struck, we haven’t seen any proportional response, “simultaneous” or otherwise, from Iran. The legality of the U.S. strike is, at best, highly questionable.

Of course, we all know that under the Constitution, Congress, not the president, has the power to declare war. We also know that for the past few decades, the executive branch has been assuming more of that power, adopting a “beg for forgiveness,” rather than an “ask for permission” stance. But no one has been as brazen about it as Donald Trump, who has bombed 7 different countries in just over a year in office and is at in a second time in Iran, after claiming, in June 2025, that he had “obliterated” their nuclear program. It’s not a good thing when the man with the nuclear codes is punch-drunk on the amount of power at his disposal, and it behooves us all to keep a close watch.

The UN Charter prohibits the threat or use of force against the territorial integrity or political independence of any state in Article 2(4), which reads, “All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.” Launching attacks, like the U.S. strike on Iran, is generally illegal. There are exceptions for self-defense against an armed attack (Article 51) or an attack authorized by the Security Council, but neither of those is in play here.

Treaties ratified by the U.S. Senate, like the UN Charter, have the status of federal laws under Article VI, Section 3 of the Constitution, which reads, “This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land.” (emphasis added). Upholding them is part of a president’s duties and the oath of office he takes under the “take care” clause of the Constitution.

If you want to read about this in more detail, there is an excellent explainer from Just Security at NYU Law in the context of Venezuela. (Full disclosure: I’m a member of the Board of Editors at Just Security.)

Tess Bridgman, President Obama’s Deputy Legal Advisor on the National Security Council, with whom we discussed war powers in January, posted this on Bluesky:

“To: House and Senate Foreign Relations, Armed Services, and Judiciary Committees:

Time to stand up for Art. I of our Constitution and the representatives of the people deciding when to go to war, not the whims of one man in the White House (or Mar-a-Lago).”

Tess and her co-author Brian Egan have a backgrounder here.

Senate Minority Leader Chuck Schumer called for Congress to return to Washington immediately, so it could vote on a War Powers Resolution. But whether Republicans will agree to impose a legislative check on military action isn’t at all clear. While the strikes on Iran are very likely illegal under both U.S. and international law, the regime itself is very unpopular, and politicians may be willing to cast aside the law in hopes of regime change (although many experts have assessed success in that regard as unlikely). Schumer tweeted:

“The administration has not provided Congress and the American people with critical details about the scope and immediacy of the threat. Confronting Iran’s malign regional activities, nuclear ambitions, and harsh oppression of the Iranian people demands American strength, resolve, regional coordination, and strategic clarity. Unfortunately, President Trump’s fitful cycles of lashing out and risking wider conflict are not a viable strategy.

The administration must brief Congress, including an immediate all senators classified briefing and in public testimony, to answer these vital questions. The Senate should quickly return to session and reassert its constitutional duty by passing our resolution to enforce the War Powers Act.”

So, legally, the administration is on thin ice under both U.S. law and international law. But many people will be pleased to see a ruthless dictator, one who gruesomely killed tens of thousands of his own people, done in. They may be willing to ignore legal niceties to get there.

That sort of rationale underscores the importance of holding fast to the rule of law and insisting that the Trump administration comply with it. Today, people may try to justify ignoring the law because they think it will lead to regime change. They may claim that it will benefit the Iranian people, as well as our own country. The law could be ignored.

But who gets to decide when the end justifies the extra-legal means and when it’s acceptable to ignore a law that stands in the way of certain actions? Is it you? Me? Donald Trump? Stephen Miller? You can readily see the problem with abandoning it.

Laws provide us with fairness and stability. They prevent arbitrary exercises of power and protect rights. They ensure justice. When you get right down to it, they prevent chaos. And the rule of law is preferable to the rule of dictators.

Like this guy, and the people who shamelessly lied to Americans during the campaign—and continue to do so.

As we evaluate what happens in the days ahead, we need to insist that the administration do this the right way. Senator Schumer is on the right track. Congress has to follow through.

Tonight’s piece isn’t about the hot take of the hour. It’s about the guardrails. We’re talking about first principles — why the rule of law exists, why it restrains all of us (especially the powerful), and why “doing whatever feels good in the moment” has never been a substitute for constitutional order. These aren’t abstract debates. They determine whether we live in a country governed by laws or by impulse.

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We’re in this together,

Joyce