President-elect Trump is ramping up speculation about his endgame with Greenland as he doubles down on calls to acquire the Danish territory, putting observers and allies alike on edge. Trump on Tuesday reiterated his desire to purchase the island during a press conference at Mar-a-Lago, the same day his son, Donald Trump Jr., made a visit there.  Observers have waved off the idea that the U.S. would realistically acquire Greenland. But President-elect Trump’s comments have nonetheless raised concerns, as well as renewed focused on the strategic importance of the island amid growing tensions with other Arctic players like China and Russia. “It’s not clear yet what the endgame is,” said Rebecca Pincus, the director of the Polar Institute at the Wilson Center, a global affairs think tank. “Denmark is a founding member of NATO, and both the Danish and Greenlandic governments expressed pretty firm opposition to a sale of Greenland. I think that would be very, very challenging.”  Greenland has been of strategic importance to the U.S. at least since the beginning of the Cold War, when the so-called GIUK gap — the stretch of water between Greenland, Iceland and the U.K. — was essential in helping contain the Soviet navy. "There is an argument that the North Atlantic matters, and because the North Atlantic matters, Greenland matters. Now there's a separate question, whether the United States needs to own it,” said Jon Alterman, senior vice president and Zbigniew Brzezinski chair in global security and geostrategy at the Center for Strategic and International Studies. "The Danish response is, 'We've been cooperating with you on this for three quarters of the century, there's no need to change the status quo.'" Alterman added that Trump likes to get attention and keep people on their toes, and “this is an example of persuading people that what they thought was settled isn't settled.” "So even if you're not talking about if the United States is going to buy Greenland next week, the sense that this administration will not be satisfied with the status quo sends a message to U.S. adversaries and allies alike that the U.S. considers the world in play,” he said. Daniel Fried, former U.S. ambassador to Poland and a fellow at the Atlantic Council, pointed to the 1951 treaty that gave the United States enormous control over Greenland’s defense. The treaty came after then-President Truman made “some halfhearted attempt” to buy Greenland in 1946. “It's an agreement that's existed for so long that people have forgotten it, but it does,” Fried said. "Trump is right that the United States has security interests in Greenland. And if this agreement is inadequate, I'd like to know why and where it has fallen short, because it's not been a problem.” “And I don't think they’ve made the case for why Greenland's importance justifies this kind of threat and bullying,” he added. “Denmark has been a serious contributor to common security.” Trump’s expressed interest in Greenland in recent weeks is not the first time he has mentioned the U.S. possibly acquiring the island. He first mentioned it as a possibility in 2019 during his first term in office, reportedly proposing that Denmark trade Puerto Rico for it.  Those plans never materialized, but Trump has put a renewed focus on obtaining it during the transition to his second term.  He reiterated his belief that the U.S. must acquire Greenland on two occasions on Tuesday, first calling into a meeting that his son was holding with some Greenlandic people. He referred to Greenland as “a very special place” that needs security both for itself and the world.  “We’re going to treat you well,” Trump said.  He later said at a press conference that he would not commit to not using economic or military force to take control of Greenland, along with the Panama Canal, and expressed concern about Chinese and Russian influence in the region. Trump also vowed to levy tariffs on Denmark if it refuses to give up Greenland.  Denmark has owned Greenland for a few centuries and has gradually granted the island in the North Atlantic and Arctic oceans greater autonomy. Greenland voted for self-government in 2008, receiving control of domestic affairs while Denmark retains responsibility for foreign affairs, including defense.  The acquisition of Greenland has been floated multiple times over that period in U.S. history, but the prospect never progressed to a sale.  Both Denmark's and Greenland’s governments have been steadfast in rejecting the idea of Greenland joining the U.S.  Danish Prime Minister Mette Frederiksen told a local TV station Tuesday that Greenlandic Prime Minister Múte Egede has been “very, very clear” that “Greenland is not for sale and will not be in the future.” She said the Greenlandic people have indicated support for that as well.  “We must not lose our long struggle for freedom,” Egede said last month, responding to Trump.  While experts cast doubt on the chances of an acquisition, they noted the strategic role of Greenland in the international order and argued that a strong U.S. presence in the area is critical to national security goals.  Alterman told The Hill that the president-elect “likes doing things and seeing what the reaction is.”  “One of the other things he has is a certain willingness to experiment and to do things over and over again and judge which approach does better,” he said. “I think his approach to his rallies was like a stand-up comedian honing an act. He means to elicit a response. He looks at the response and then he adapts.” Pincus said Greenland’s geographic position is strategically significant, but it also has a “wealth” of natural resources including rare minerals and a “limitless potential” for hydropower from the Greenland ice sheet.  “You pair all those strengths and attributes with the population pursuing independence, it's easy to understand why there would be increased interest in it,” she said.  Romain Chuffart, the president and managing director of the Arctic Institute, pointed to Egede’s statement Tuesday that “[our] future and fight for independence is our business.” He noted that part of Greenland’s foreign policy strategy for the next decade is “nothing about us, without us.”  Even with Trump pushing for acquisition and Denmark and Greenland soundly rejecting it, Chuffart said he views the chances of a standoff between the countries as “highly improbable.” But if one were to occur, it could damage U.S. credibility internationally, he added.  “If such a scenario were to occur, it would represent a significant failure of U.S. diplomacy and deal a serious blow to the country's foreign policy credibility on the global stage,” Chuffart said.  Jim Townsend, a former deputy assistant secretary of Defense for European and NATO policy, acknowledged that China and Russia have been seeking to increase their influence in the region, as Trump has argued, but he said attempting to purchase Greenland is not the best way to address the issue.  He mentioned the U.S. purchase of Alaska from Russia in 1867 for strategic purposes and pointed out the world operates differently than it did then.  “If there’s an issue here, you meet with the Greenlanders and with Denmark to try to fix what the U.S. is concerned about,” Townsend said.