Greenland invasion could spark US constitutional crisis, experts say

With the crisis over Greenland is fast approaching a transatlantic breaking point, the world is focused on the European reaction to Donald Trump’s possible land grab.

But domestically, his Greenland plans could further fire up an already vocal Congressional opposition and eventually lead to his impeachment, if not trigger a constitutional crisis, according to several experts in United States law who spoke to Euronews.

Over the last few days, a series of opinion polls published in the US showed that there is overwhelming public opposition to the annexation of Greenland, and that a scenario involving which military force has practically zero public support.

But is Trump’s sabre-rattling just a bluff?

“Most people still doubt that Trump is serious about it and that he would blow up NATO and start a war with Europe,” said Harold Honju Koh, a professor of international law at Yale University and a former legal adviser to the US State Department.

“But as soon as we have boots on the ground there, the blowback will be gigantic. Nobody wants their child to die in a pointless conflict.”

The question is: does Trump have the authority to invade Greenland?

An act of war

“No, he has not,” said Carrie Lee, Senior Fellow at the Democracy and Security Network at the German Marshall Fund of the United States in Washington.

An invasion of Greenland would be an act of war against a treaty ally for which Trump would need Congressional authorisation, Lee explained. As enshrined in Article I, Section 8 of the US Constitution, Congress, not the president, has the power to declare war.

Article 2 of the Constitution specifies that the president is commander-in-chief of the US armed forces, but that authority is generally understood to apply only once hostilities are authorised or in emergencies.

Presidents can use military force without prior Congressional authorisation only in limited circumstances: self-defence, protection of US citizens or short-term military actions.

An unprovoked invasion of Greenland would be offensive, not defensive, would target a NATO ally, and would lack any plausible claim of imminent threat. It would far exceed the scope of unilateral presidential war powers recognised since World War II.

This would place it far outside accepted constitutional practice. Lee said that so long as there is no pretext that would justify military force, such as a Danish attack on a US ship, an assault on Greenland would be “naked aggression”.

Then there is Article 50 of the Charter of the United Nations, dating from 1945, which prevents the use of force against another state without credible claim of self-defence.

“This was ratified by the US and has therefore become domestic law,” Lee said.

In addition, the UN Charter protects the people affected most by Trump’s possible land grab: the Greenlanders themselves.

“The right of self-determination would be violated if Denmark ceded Greenland to the United States without popular support in Greenland in favour of such a transfer of territorial title, even if this were a completely peaceful process,” wrote Jure Vidmar, professor of Public International Law at Maastricht University, in a research note.

“Greenland cannot be ceded without the consent of its people.”

So far, opposition in Congress to action against Greenland is building, even within Trump’s own Republican Party, which usually follows him in lockstep. At the time of writing, only one Republican Senator, Ted Cruz of Texas, has backed Trump on Greenland.

The Senate and the House can pass legislation to tie Trump’s hands, but the president can veto it. Such a veto can be overridden by a two-thirds majority in the Senate – a tall order given the sharp partisan divide in the Capitol.

But Republican Senator Thom Tillis from North Carolina, who is retiring at the end of this Congress, predicted members of both parties would come together if it became clear Trump was actually ordering the military to get ready.

“If there was any sort of action that looked like the goal was actually landing in Greenland and doing an illegal taking … there’d be sufficient numbers here to pass a war powers resolution and withstand a veto,” Tillis said.

If Trump ignores Congress’ resolution on Greenland, lawmakers have another tool at their disposal: they could simply withdraw funding for the military operation, something Congress did during President Richard Nixon’s second term, accelerating the end of the war in Vietnam.

That traumatic experience led Congress to pass the War Powers Resolution (WPR, often known as the the War Powers Act) in 1973, designed to limit the president’s power to commit troops to armed conflict without Congressional approval.

Under the WPR, Congress can order US forces to withdraw within 60-90 days if the legislative branch doesn’t authorise the action and demand hearings, subpoenas and testimony from military and civilian officials.

If Trump ignored such measures, that’s where the constitutional crisis begins – a situation where two branches of government issue conflicting claims of authority.

The impeachment scenario

Congress could hold Trump in contempt and start impeachment proceedings to drive him out of office. Republican Congressman Don Bacon from Nebraska is already predicting such a scenario, calling Trump’s Greenland obsession “the dumbest thing I’ve ever heard”.

In case of an invasion of Greenland, Congress could argue that Trump abused his power, violated the Constitution, and violated treaty obligations which are part of US law under the Supremacy Clause (Article VI, Section 2 of the US Constitution), which establishes that the Constitution, federal law and treaties are “the law of the land” – meaning they take precedence over everything else.

However, impeachment proceedings need to originate in the House of Representatives where the Republicans hold a majority, albeit a razor-thin one.

“What Trump has done in Venezuela and plans to do in Greenland is unprecedented and plainly unconstitutional,” said Bruce Ackerman, a prominent legal scholar at Yale Law School. “But the Republican majority, largely composed of Trump hardliners, controls the agenda and can block any floor vote.”

Eventually, only a Democratic victory in the midterm elections in November could truly alter the balance of power on Capitol Hill.

In addition, the WPR is “tricky legislation”, according to Lee, as its constitutionality remains a subject of intense, ongoing legal debate.

While presidents have often viewed it as an unconstitutional encroachment on executive authority, supporters of the WPR saw it as a necessary assertion of Congress’s constitutional role in war-making.

“All presidents ever since have complied with the letter of the Resolution, while also saying it was not binding,” she added. “So it’s not clear whether Trump would violate the War Powers Resolution by invading Greenland.”

However, she added that “it would become a bigger constitutional crisis, if the president orders the military to attack a treaty ally and not a bunch of drug smugglers. It would be extremely difficult to make the case that (the invasion of Greenland) is lawful.”

If Trump were to issue such an order, the military command would move from the president to the secretary of defence to the respective commander overseeing the operation.

“At that point, the commander would have to make the decision whether to follow the order, likely based on some fig leaf legal justification, or not. So the question is, are these orders lawful?”

The US military is bound to obey lawful orders and trained to refuse unlawful orders. Invading Greenland without congressional authorisation, against a NATO ally, and in violation of treaty obligations would raise serious legality concerns.

“The only response of the commander should be: I can’t follow this order,” Lee said.

And yet, it’s more complicated. US military officers swear to support and defend the Constitution, which is the supreme law, rather than swearing allegiance to a single person or political party.

Enlisted service members take a similar oath, but add a commitment to “obey the orders of the president of the United States and the orders of the officers appointed over me”. A subtle difference.

In 2016, Professor Ackerman served as legal counsel to US Army Captain Nathan Michael Smith, who took then-President Barack Obama to court over the fight against the Islamic State in Iraq and Syria. His argument was that Obama violated the WPR by continuing the conflict without Congressional support within the law’s timeframe.

After a district court dismissed the lawsuit as a “political question”, Ackerman appealed and lost again. The case did not move up to the Supreme Court, almost a decade after the original trial, Ackerman suggested a similar case could reach that level.

“It is still a question in history that might take years to be entirely resolved,” he said.

Among the consequences of Trump’s possible military action, then, would be both a challenge to the military chain of command and a potentially enormous legal battle.

The US system is ostensibly designed to prevent presidential overreach, but an invasion of Greenland would push it closer to the edge than almost any scenario short of domestic authoritarian measures.

“The thing is that none of this is forced upon us, none of this is done for meaningful purposes,” said Professor Koh. “It’s clearly a war of choice.”