Sen. Chris Murphy said in an interview on NBC News` "Meet the Press" that if the U.S. annexed Greenland, "it would be the end of NATO."

The Connecticut Democrat`s comments came in response to a question about whether the move floated by the Trump administration would effectively end the North Atlantic Treaty Organization, a defensive alliance created in the years after World War II.

"NATO would have an obligation to defend Greenland, and so query whether we would be at war with Europe, with England, with France," Murphy said.

Greenland is a territory of Denmark, a NATO member. Article 5 of the NATO Charter stipulates that an attack on one NATO member should be considered an attack on all NATO members. Article 5 has only been invoked once, in support of the U.S. following the Sept. 11, 2001, attacks.

Shortly after the U.S. operation to capture Nicolás Maduro, President Donald Trump`s ally Katie Miller posted a picture on social media of the American flag on Greenland, writing, "SOON!"

Greenland Prime Minister Jens-Frederik Nielsen condemned Trump`s push to take control of the territory, saying it was "so disrespectful." Reuters reported that Mette Frederiksen, Denmark`s prime minister, told the public broadcaster DR that "if the United States attacks another NATO country, everything stops."

Murphy argued in the interview that Trump was not focused enough on the American people.

"Let`s also talk about what`s at stake here," he said. "The president is spending every single day thinking about invading Greenland, managing the Venezuelan economy, building a ballroom. He is not thinking about the American people at all."

Other Democrats struck similar tones, warning that U.S. action against Greenland could potentially lead to the end of the NATO alliance.

Sen. Mark Warner, D-Va., said in an interview on "Fox News Sunday" that if Trump "were to take an action against Greenland, that would completely destroy NATO."

Similarly, Sen. Mark Kelly, D-Ariz., said in a post to X that if the Trump administration were to pursue taking Greenland by force, "this President is dumber and more incompetent than most of us thought."

"Add an unqualified Secretary of Defense and we have the recipe for the biggest geopolitical blunder by the United States in our country`s history," he added.

Sen. Tim Kaine, D-Va., said in an interview on CBS News` "Face the Nation" that he believed Congress would be able to stop Trump if he tried to take Greenland.

"We will force a vote in the Senate about no U.S. military action in Greenland or Denmark if we need to," he said. "We will get overwhelming bipartisan support that this president is foolish to even suggest this."

Sen. Rand Paul, R-Ky., also criticized White House rhetoric about Greenland in an interview with ABC News` "This Week."

He discussed the possibility of the U.S. trying to buy Greenland, saying, "You don`t get there by angering and denigrating the people who live there and saying, `We`re going to march the Marines in and take if you don`t sell it to us.`"

"It doesn`t make them very willing sellers," he added.

The White House has framed the administration`s desire to control Greenland as a "national security priority." White House press secretary Karoline Leavitt said the administration has not ruled out using the military to take control of Greenland. The U.S. already has a military base in Greenland.

"The President and his team are discussing a range of options to pursue this important foreign policy goal, and of course, utilizing the U.S. Military is always an option at the Commander in Chief`s disposal," she said in a statement.

Late last week, Trump escalated the rhetoric, saying, "We are going to do something on Greenland, whether they like it or not." He claimed the territory would otherwise be taken over by Russia or China.

Last week, Trump posted on Truth Social that he doubted whether NATO "WOULD BE THERE FOR US IF WE REALLY NEEDED THEM" but acknowledged that U.S. would "always be there for NATO, even if they won`t be there for us."

In a New York Times interview published later in the week, the president acknowledged that "it may be a choice" between preserving the NATO alliance or acquiring Greenland.