President Donald Trump's push to acquire Greenland has sparked a backlash from Republicans in Congress, as lawmakers voice growing concern about US military interventions overseas.
But it remains unclear if enough Republicans are willing to join Democrats to block a takeover of the island territory - and whether Trump would bow to pressure from Congress, or act alone as he's done several times in a second term marked by growing American entanglements abroad.
The focus on Greenland has grown into a broader discussion over the Trump administration's unilateral use of military force, along with diplomatic and economic coercion, to project power in Venezuela, Iran, and elsewhere around the world.
Republicans have largely backed Trump's foreign policy agenda since he returned to the White House. But now, a growing number are siding with Democrats in Congress and NATO allies who say a takeover of Greenland would violate US and international law.
In recent days, some Republican leaders have said there's little interest in the US buying Greenland or seizing it through military force. Some Republican lawmakers have also joined Democrats in opposing a new plan by Trump to place tariffs on countries that don't back his bid to acquire the territory, which is self-governed but controlled by Denmark.
The proposed tariffs would be bad for America, bad for American businesses, and bad for America's allies, Senator Thom Tillis of North Carolina wrote on social media, adding that the move would benefit China and Russia. It's great for Putin, Xi and other adversaries who want to see NATO divided.\
Other Republicans said Trump's ambition to annex Greenland was threatening to undermine the NATO alliance - to which both the US and Denmark belong - in a moment of growing tension between the US and European allies.
Trump has argued the US must own the territory to better compete with China and Russia in the Arctic, and has vowed to take it one way or another. On Tuesday, the US president downplayed concerns that the issue was hurting NATO when asked by the BBC if he was willing to see the decades-old security alliance collapse as a consequence of his push for the territory. Trump reiterated his view that ownership of Greenland was critical for US and global security.
Congress has some options to try to reign Trump in if Republicans and Democrats do choose to pick a fight with the president over Greenland. Congress has the power of the purse and would have to approve funding used to buy Greenland. Denmark and Greenland have both insisted the island isn't for sale. If Trump wants to buy Greenland it would require an act of Congress to provide the funds to do so, said Daniel Schuman, executive director of the American Governance Institute. It's unlikely that Congress could repurpose existing funding to buy the territory.
Lawmakers worried about a military incursion in Greenland have signalled support for measures prohibiting any US action without congressional approval. However, it's unclear if the proposals have sufficient Republican support to pass in either chamber of Congress.
Some Republicans have already indicated that they'd consider breaking with Trump over Greenland. Senator Mitch McConnell of Kentucky, the former majority leader, told reporters that a US takeover of the territory would shatter the trust of allies.
Faced with growing Republican concern over Greenland, Trump could look to strike a deal that falls short of a formal treaty and doesn't require Senate approval. However, it's unclear if presidents have the authority to make such agreements without input from Congress. 'Plenty of international agreements are concluded in forms other than treaties,' said Josh Chafetz, a professor at Georgetown Law, but 'I'm sceptical that something of this magnitude could be concluded as a pure executive agreement.'
Trump did not say on Tuesday whether he believed he was constrained by anything 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,' he said.
