Trump Greenland Gambit Bolsters NATO Mission, Avoids Illegal War

President Donald Trump said that he wouldn’t use force to take Greenland in his remarks in Davos, which is consistent with the rule of law. A US military invasion of Greenland would be unlawful under US and international law, unlike the Jan. 3 Venezuela raid.

In the Jan. 21 Davos speech, Trump reiterated his commitment to bringing peace in the Russia-Ukraine war to avoid a reprise of world war implicating nuclear weapons, the core concern of the UN Charter, and announced a commitment to working with NATO to formulate a new framework for Greenland.

Under US law, a contested invasion of Greenland would rise to the level of war requiring explicit congressional authorization under the Declare War Clause of the US Constitution. The two-part test that the Department of Justice’s Office of Legal Counsel, or OLC, uses to assess the domestic legality of the president’s use of kinetic force abroad asks whether there are “important national interests” at stake and whether the “anticipated nature, scope and duration” of operations rises to the level of “war in the constitutional sense.”

The first prong is easily met because of Greenland’s natural resources and critical location in the North Atlantic and Arctic Oceans, a domain of brewing competition with China and Russia. Greenland has always been an important US national interest. In April 1941, the US deployed Coast Guard units to Greenland to ensure US access and deny Nazi Germany access to cryolite (an essential airplane metal) and bases before the US and Germany were at war.

Franklin D. Roosevelt, like Trump, was fixated on the US national security interest in Greenland. The US military intervention was legally justified as an invitation, on a then-dubious basis of an executive agreement signed by the US Secretary of State and the ex-Danish minister in DC who was charged with treason by the lawful but Nazi-collaborationist Danish government.

In fact, until the early 20th century, the US had firmly rejected Danish or other European claims to Greenland, situated in the Western Hemisphere, under the Monroe Doctrine. The US only recognized Danish sovereignty over Greenland in 1916 as a quid pro quo for a contract of sale of the Danish West Indies to the US (now the US Virgin Islands).

But the second prong—military operations that don’t rise to the level of “war in the constitutional sense”—poses a real constraint on invading foreign sovereign territory by contrast to air strikes or commando raids. The OLC in 2011 under President Barack Obama and in 2018 under Trump characterized “prolonged and substantial military engagements, typically involving exposure of US military personnel to significant risk over a substantial period” as operations for which the president must seek prior congressional approval.

Invasions almost always would seem to count, although the OLC has signed off on—and Congress as a body didn’t reject as unlawful— invasions in Grenada (1983), Panama (1989), and Haiti (1994) against dictators to restore democracy and to protect American lives.

But neither of those conditions—dictatorship or American lives in immediate danger—are present in Greenland, despite its strategic importance to the US. Consequently, as a matter of US domestic law, Trump would need prior authorization from Congress to invade Greenland.

It’s also plain that US invasion of Greenland would violate international law. Article 2(4) of the UN Charter requires members to “refrain” from “the threat or use of force against the territorial integrity or political independence of any state.”

The charter lists two exceptions: UN Security Council authorization under Article 42 and “the inherent right of individual or collective self-defense” under Article 51. And post-World War II customary international law anchored in what states have done has evolved to encompass three more exceptions: invitation and using armed force to stop humanitarian crises or to stop the use of weapons of mass destruction.

There is no argument for international legality of use of force against Greenland under any of these five grounds. The Security Council hasn’t authorized US military action against Greenland. There is no evidence of a humanitarian crisis and use of weapons of mass destruction in Greenland. By contrast to the 1941 executive agreement, there is no basis to argue invitation.

Even self-defense, which has been the most shapeshifting of the five lawful grounds for war, is a bridge too far. Self-defense requires that the US was attacked or faces imminent attack, but there is no indication that Greenland or Denmark will attack the US or is “unwilling or unable” to act if the US is attacked.

What’s evident from Trump’s remarks at Davos and his commitment to work with NATO going forward to address US national interests in Greenland is that his talk about invading Greenland was just talk to bring NATO members to the table, not a real “threat” under Article 2(4) of the UN Charter. He didn’t order any US amphibious readiness or aircraft-carrier strike groups into the Northern Atlantic in January; nor does there seem to have been any recent increase in US military personnel and materiel in Greenland. Pentagon sources confirmed that they weren’t asked to draw up operational plans to invade Greenland (or dust off WWII-era operational documents like tide charts).

And his stratagem appears not only to have worked but also to have reinforced NATO’s principal mission: a trans-Atlantic collective self-defense alliance against the former Soviet Union and its allies. NATO isn’t a mutual non-aggression pact—that’s why Article 5 of the NATO Treaty doesn’t address uses of force among NATO members which have occurred episodically as between the UK and Iceland over fishing disputes and between Greece and Turkey over Cyprus.

The bottom line is the denouement of the Greenland episode that Trump engineered at Davos doesn’t mean the end of international law restricting the use of force in world affairs. Rather, he has reinforced the fact that the UN Charter is about preventing World War III among the most powerful nuclear states. And doing so requires jolting our allies and partners out of their old complacency and inertia.

This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law, Bloomberg Tax, and Bloomberg Government, or its owners.

Author Information

Thomas H. Lee is a professor at Fordham Law School and author of the forthcoming book, “Justifying War.” He was also a senior Pentagon lawyer in the first Trump administration and a US naval cryptologist.

Write for Us: Author Guidelines