UPDATE: The Supreme Court Issues Ruling Declaring Any Military Operation Against Greenland Without Explicit Congressional Authorization a Criminal Act, Warns Generals and Soldiers They Will Be Prosecuted for Following Illegal Donald Trump Orders

Supreme Court Rules Unauthorized Military Action Against Greenland Would Be Criminal, Reasserts Congressional Authority Over War

In a landmark decision with major implications for U.S. war powers and military accountability, the Supreme Court ruled this week that any use of military force against Greenland without explicit authorization from Congress would constitute an illegal act. The Court further stated that members of the United States Armed Forces—from commanding generals down to enlisted personnel—could face federal prosecution for participating in such an operation under “illegal orders.”

The ruling, decided 7–2, directly addresses concerns raised in recent months about possible unilateral military action in the Arctic region. The majority opinion emphasized that the U.S. Constitution assigns Congress—not the President—authority over declarations of war, and that this separation of powers cannot be bypassed through executive directives.

Reasserting Constitutional War Powers

Writing for the majority, the Court held that “the use of armed force against a recognized foreign territory without congressional approval constitutes an unlawful act under both constitutional and statutory frameworks.” The justices cited both Article I of the Constitution and decades of precedent limiting unilateral military action by the executive branch.

This decision reaffirms that the President is not granted a blank check to initiate war,” the opinion stated. “Congress holds the power to declare and authorize war, and the military must operate within those boundaries.”

Legal scholars note that the decision significantly clarifies the long-debated gray area around so-called “limited” or “preemptive” military actions initiated without legislative approval.

Personal Liability for Military Personnel

Perhaps the most striking element of the ruling is the Court’s warning to military members themselves. The justices concluded that soldiers do not have immunity if they knowingly participate in an unlawful use of force—even if ordered to do so by superiors.