Can the U.S. Congress stop Trump from occupying Greenland?

President Donald Trump’s push to acquire Greenland has sparked a backlash from congressional Republicans, who have expressed growing concern about U.S. military intervention abroad.

But it’s unclear whether enough Republicans are willing to join Democrats in blocking a takeover of the island territory, and whether Trump will bow to pressure from Congress or act alone, as he has done many times during his second term amid growing U.S. entanglements overseas.

The focus on Greenland has grown into a broader discussion of 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.

Since Trump returned to the White House, Republicans have largely supported his foreign policy agenda. But now, a growing number of people are siding with congressional Democrats and NATO allies who argue that taking over 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 through military force. Some Republican lawmakers have also joined Democrats in opposing a new Trump plan to impose tariffs on countries that do not support his acquisition of the territory. The territory is autonomous but controlled by Denmark.

North Carolina Sen. Thom Tillis wrote on social media that the proposed tariffs would be “bad for America, bad for American businesses, and bad for American allies,” adding that the move would benefit China and Russia. “That’s a good thing for (Russian President Vladimir) Putin, (Chinese President) Xi Jinping and other adversaries who want to see NATO split.”

Other Republicans said Trump’s ambition to annex Greenland could undermine the NATO alliance of which the United States and Denmark are members at a time of growing tensions between the United States and European allies.

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

Trump argued that the United States must own the territory to better compete with China and Russia in the Arctic and vowed to treat it “some way.”

The US president played down fears the issue was hurting Nato when asked by the BBC on Tuesday whether he would like to see the decades-old security alliance collapse over his bid for territory. Trump reiterated his view that ownership of Greenland is vital to U.S. and global security.

“We need (Greenland) for national security, and indeed world security,” he said.

But Trump’s insistence on acquiring the territory has become increasingly unpopular on Capitol Hill.

If Republicans and Democrats do choose to spar with the president over Greenland, Congress has some options to try to restrain Trump.

Experts say Congress has fiscal powers and would theoretically have to approve the money to buy Greenland. Denmark and Greenland both insist they will not sell the island.

“If Trump wants to buy Greenland, it will require Congressional action to provide the funding,” said Daniel Schumann, executive director of the Institute for American Governance and an expert on congressional procedures. Schumann added that Congress was unlikely to repurpose existing funds to purchase the territory.

Still, the administration has expanded its use of executive power to shape Trump’s immigration and tariff agenda, among other issues. Schuman said the administration may try to claim some new powers to seize Greenland, overriding any congressional obstacles.

Lawmakers concerned about a military invasion of Greenland have expressed support for measures that would ban the United States from taking any action without congressional approval. But it’s unclear whether the proposals have enough Republican support to pass both houses of Congress.

Earlier this month, five Senate Republicans joined Democrats in advancing a bill that would prevent the government from taking further military action against Venezuela following the December attack that ousted former President Nicolas Maduro.

The Venezuela War Powers Resolution ultimately failed to pass the Senate. But it shows growing dissatisfaction among Republican and Democratic lawmakers over Trump’s use of military force overseas after campaigning in 2024 on a pledge to reduce U.S. involvement in foreign conflicts. A bipartisan congressional delegation visited Denmark last week in a symbolic show of support for Greenland.

It’s unclear how the Senate, which is responsible for ratifying the treaty, would respond if the United States and Denmark reached some kind of deal to take over part or all of Greenland.

The United States and Denmark reached an existing arrangement in 1951 that allows the United States to expand its military presence in Greenland. Murkowski and other Republicans believe the United States does not need to take over the territory to address national security needs in the region.

If the U.S. and Denmark reach a deal, the Senate may try to block Trump by opposing a treaty between the U.S. and Denmark. The treaty requires the support of two-thirds of the Senate for ratification, and Republicans currently fall well short of that.

Some Republicans have said they would consider breaking with Trump on Greenland. Former upper house majority leader Mitch McConnell of Kentucky told reporters that a U.S. takeover of the territory would “shatter the trust of our allies.”

Faced with growing Republican concerns about Greenland, Trump may seek to strike a deal that is not consistent with a formal treaty and does not require Senate approval. But analysts say it’s unclear whether the president has the authority to reach such a deal without input from Congress.

“Many international agreements are made in forms other than treaties, but I’m skeptical that an agreement of this magnitude could be reached as a purely enforcement agreement,” said Josh Chafetz, a professor at Georgetown University Law School.

Trump did not say Tuesday whether he believed he was subject to any restrictions in his pursuit of Greenland. Asked how far he was willing to go, Trump told reporters to stay tuned.

“I think something is going to happen that’s going to be very good for everybody,” Trump said.

Additional reporting by Kayla Epstein