As President Donald Trump renews calls for the United States to “claim” Greenland, international law is emerging as the central constraint. It’s clear under international law and the UN treaty that military force and global intimidation cannot be used to change borders in the modern era.
Greenland is a self-governing territory within the Kingdom of Denmark. Denmark’s Self-Government Act explicitly recognizes Greenlanders as a people with a right to self-determination under international law, while leaving sovereignty and external affairs with the Danish realm.
That structure matters: any transfer of territory would require lawful consent processes involving Denmark and, critically, the people of Greenland.
A unilateral declaration by an American president that he must have Greenland for whatever reason has no weight under international law.
International law’s first “pushback” is the prohibition on acquiring territory by force or threat of force, a principle rooted in the U.N. Charter and reinforced by allied commitments to peaceful dispute resolution.
Trump said this week he would not use force, after days of ambiguity that alarmed European officials.
The second pressure point is self-determination. U.N. human-rights experts warned that Greenlanders must be free to determine their political status “without external coercion or interference,” citing treaty obligations and Indigenous rights standards.
That framing raises the bar for any campaign that relies on coercive leverage, such as punitive tariffs or other economic threats to compel a territorial outcome.
Supporters of Trump’s approach argue Greenland is strategically vital for Arctic security and missile defense. International law does not bar negotiated arrangements if Denmark and Greenland freely consent.
Guest:
Tara Van Ho is an associate professor at the St. Mary's School of Law.
"The Source" is a live call-in program airing Mondays through Thursdays from 12-1 p.m. Leave a message before the program at (210) 615-8982. During the live show, call 833-877-8255, email thesource@tpr.org.
This episode will be recorded on Thursday, January 22, 2026, at 12:30 p.m.
