Could the US Congress stop Trump from taking Greenland?

President Donald Trump’s efforts to acquire Greenland have sparked a backlash from congressional Republicans, as lawmakers express growing concern about U.S. military interventions abroad.

But it remains unclear whether enough Republicans are willing to join Democrats in blocking a takeover of the island territory — and whether Trump would cave to congressional pressure or act alone as he has repeatedly done during a second term marked by increasing U.S. interference abroad.

The focus on Greenland has evolved into a broader debate over the Trump administration’s unilateral use of military force, as well as diplomatic and economic coercion, to project power in Venezuela, Iran and elsewhere around the world.

Republicans have largely supported Trump’s foreign policy agenda since his return to the White House. But today, a growing number of people are siding with congressional Democrats and NATO allies, who say a takeover of Greenland would violate U.S. and international law.

In recent days, some Republican leaders have said the United States has little interest in buying Greenland or seizing it by military force. The White House had previously left the military option on the table, but Trump ruled it out Wednesday in his speech at the World Economic Forum in Davos.

Some Republican lawmakers also joined Democrats in opposing a new plan by Trump to impose tariffs on countries that do not support his bid to acquire the territory, which is self-governing but controlled by Denmark.

The proposed tariffs would be “bad for America, bad for American businesses, and bad for America’s allies,” North Carolina Sen. Thom Tillis wrote on social media, adding that the move would benefit China and Russia. “It’s great for [Russian President Vladimir] Poutine, [Chinese President] XI [Jinping] and other adversaries who want to see NATO divided.”

Other Republicans said Trump’s ambition to annex Greenland threatened to undermine the NATO alliance – to which the United States and Denmark belong – at a time of growing tension between the United States and its European allies.

“Respect for the sovereignty of the people of Greenland should be non-negotiable,” Sen. Lisa Murkowski, co-chair of the Senate Arctic Caucus, said in a statement.

Trump argued that the United States needed to possess the territory to better compete with China and Russia in the Arctic, and vowed to take it “one way or another.”

On Tuesday, the US president played down concerns that the issue was harming NATO when asked by the BBC whether he was prepared to see the decades-old security alliance collapse as a result of his push for territory. Trump reiterated his view that ownership of Greenland was essential to the security of the United States and the world.

“We need [Greenland] for national security and even global security,” he said.

But Trump’s insistence on the territory is increasingly unpopular on Capitol Hill, as more Republicans have come forward to publicly break ranks.

Rep. Don Bacon of Nebraska, a Trump critic, said Trump’s efforts on Greenland could lead to an impeachment inquiry. And Republican leaders in each chamber of Congress, Senate Majority Leader John Thune and House Speaker Mike Johnson, have said they oppose military intervention in Greenland, while Trump has refused to rule out the possibility.

Other Republicans have expressed support for Trump. Sen. Ted Cruz of Texas said Sunday that it was “extremely in America’s national interest” to own Greenland.

“As it relates to Greenland, I want to commend President Trump for his unwavering focus on America First, on the economic and national security interests of the United States,” Cruz said in an interview with Fox News.

Congress has several options to try to rein in Trump, if Republicans and Democrats choose to fight with the president over Greenland.

Congress has the power of the purse and should in theory approve the funding used to buy Greenland, experts said. Both Denmark and Greenland insisted the island was not for sale.

“If Trump wants to buy Greenland, it would take an act of Congress to provide the necessary funds,” said Daniel Schuman, executive director of the American Governance Institute and an expert on parliamentary procedure. It is unlikely that Congress will be able to reuse existing funds to purchase the territory, Schuman added.

Yet the administration has expanded the use of executive power to implement, among other things, Trump’s agenda on immigration and tariffs. The administration could try to claim new authority to seize Greenland, which would allow it to bypass any congressional obstacles, Schuman said.

Lawmakers worried about a military incursion into Greenland have expressed support for measures barring any U.S. action without congressional approval. But it’s unclear whether the proposals have enough Republican support to pass either chamber of Congress.

Five Senate Republicans joined Democrats earlier this month to advance a bill that would have blocked the administration from taking further military action in Venezuela, following the December attack that removed former President Nicolás Maduro.

The Venezuela War Powers Resolution ultimately failed to pass the Senate. But it speaks to growing frustration among Republican and Democratic lawmakers with Trump’s use of military force abroad, after he ran in 2024 on a promise to reduce U.S. involvement in foreign conflicts. Last week, a bipartisan congressional delegation traveled to Denmark to symbolically show support for Greenland.

It is also unclear how the Senate, which ratifies treaties, would react if the United States reached an agreement with Denmark to retake part or all of Greenland.

The United States entered into an agreement with Denmark in 1951 that allowed it to expand its military presence in Greenland. Murkowski and other Republicans have argued that the United States does not need to seize territory to meet national security needs in the region.

The Senate could try to thwart Trump by opposing a treaty between the United States and Denmark, should the two countries reach an agreement. The treaties require two-thirds support in the Senate to be ratified, something Republicans are currently far from achieving.

Some Republicans have already indicated they would consider breaking with Trump over Greenland. Sen. Mitch McConnell of Kentucky, a former majority leader in the upper house of Congress, told reporters that a U.S. takeover of the territory would “break the trust of allies.”

Faced with growing Republican concern over Greenland, Trump may seek a deal that falls short of a formal treaty and does not require Senate approval. But it’s unclear whether presidents have the authority to make such deals without input from Congress, analysts say.

“Many international agreements are made in forms other than treaties,” said Josh Chafetz, a professor at Georgetown Law, but “I am skeptical that something of this magnitude can be done in the form of a pure executive agreement.”

Trump did not say Tuesday whether he thought he would be limited by anything in his pursuit of Greenland. When asked how far he was willing to go, Trump told reporters to stay tuned.

“I think something is going to happen that will be very good for everyone,” Trump said.

Additional reporting by Kayla Epstein