Tensions have dramatically escalated between Denmark and the United States following former President Donald Trump's renewed and assertive push to acquire Greenland, explicitly refusing to rule out military force as an option. Denmark's Ministry of Defence has confirmed the continued validity of a Cold War-era rule, dating back to 1952, which instructs its troops in Greenland to "immediately take up the fight" against any invading force without awaiting formal orders, a directive widely interpreted as a "shoot first, ask questions later" policy. Trump's interest in Greenland, first publicized in 2019, has been revitalized with a focus on national security, prompting deep concern across Europe. Danish Prime Minister Mette Frederiksen has unequivocally stated that Greenland is not for sale and has warned that any attempt by the U.S. to seize the territory militarily would effectively mean the end of the NATO alliance. European leaders, including those from France, Germany, Poland, Spain, and the UK, have rallied behind Denmark, issuing a joint statement emphasizing that Greenland belongs to its people and only Denmark and Greenland can decide its future. The White House's continued refusal to disavow military options has intensified the alarm among NATO allies, who view the situation as an unprecedented challenge to the transatlantic alliance. Analysts suggest this geopolitical standoff could push U.S.-Europe relations further apart and compel Europe to accelerate its pursuit of strategic autonomy. Greenland, a semi-autonomous territory under Danish sovereignty, holds significant geopolitical and resource-rich appeal, making its future a critical point of international contention.