Greenland Claims: How Close Have NATO Members Come to Fighting Each Other?

When most people think of NATO, they imagine unity — dozens of nations bound together by shared security interests, standing firm against outside threats. But history tells a more complicated story. The recent debate surrounding Greenland, a strategically vital territory governed by Denmark, has reopened an uncomfortable but important question:

Have NATO members ever come close to fighting each other?

The short answer is yes — closer than many realize.

While NATO has never collapsed into open warfare between its own members, internal disputes, territorial disagreements, and resource conflicts have repeatedly tested the alliance. The Greenland discussion is simply the latest reminder that unity inside NATO is not automatic — it must be constantly managed.

Why Greenland Suddenly Matters So Much

Greenland may appear remote, but geopolitically, it is one of the most valuable locations on Earth. Positioned between North America and Europe, it plays a crucial role in missile defense systems, Arctic surveillance, and control of emerging shipping routes as polar ice melts.

Recent political rhetoric suggesting that Greenland’s status could be challenged for “security reasons” alarmed Denmark and raised eyebrows across NATO. Even without any real military plans, the implications were serious: one NATO member even hinting at territorial ambition toward another undermines the alliance’s foundation.

That concern echoes lessons NATO has learned — sometimes the hard way — throughout its history.

NATO’s Biggest Blind Spot

NATO’s famous Article 5 promises collective defense if a member is attacked by an external enemy. But the treaty says nothing about what happens if two NATO members confront each other.

This omission has repeatedly placed the alliance in awkward, high-risk situations.

The Cod Wars: When Fishing Led to Naval Clashes

One of NATO’s strangest — yet most revealing — confrontations came during the Cod Wars between the United Kingdom and Iceland from the 1950s to the 1970s.

At stake were fishing rights in the North Atlantic. Iceland expanded its maritime boundaries to protect its fishing industry. Britain refused to accept the change. What followed were naval confrontations involving ramming ships, cutting fishing nets, and aggressive patrols.

No one declared war, but military vessels from two NATO members directly confronted each other at sea. The crisis mattered deeply because Iceland hosted a critical NATO base used to monitor Soviet submarines. Strategic necessity eventually forced a diplomatic solution — but the episode proved that even small disputes can bring allies dangerously close to conflict.

Greece and Turkey: NATO’s Most Dangerous Rivalry

If any dispute shows how fragile alliance unity can be, it’s the long-running tension between Greece and Turkey.

The most serious moment came in 1974, when Turkey invaded Cyprus following a coup backed by Greek elements. Both Greece and Turkey were NATO members, yet found themselves on opposite sides of a military operation.

The situation nearly escalated into direct war. Greece temporarily withdrew from NATO’s military command, and U.S. diplomacy became the primary tool preventing a catastrophic alliance breakdown. Cyprus remains divided to this day, and Greek-Turkish tensions still flare periodically over airspace, islands, and maritime rights.

This episode remains the closest NATO has ever come to internal warfare.

The Turbot War: Canada vs Spain

In 1995, another unexpected NATO dispute erupted — this time over fish again.

Canada seized a Spanish fishing vessel in international waters to protect declining turbot stocks. Spain responded by deploying naval ships, and Canada openly warned it might use force if Spanish vessels resisted.

Though the standoff never turned violent, it demonstrated how resource protection and national pride can override alliance solidarity. Only international mediation prevented escalation.

Political Cracks Without Gunfire

Not all NATO conflicts involve ships or soldiers. Some of the deepest divisions have been political — and just as damaging.

The Suez Crisis (1956): Britain and France launched a military operation without U.S. support, creating a major rift inside NATO.

Vietnam War era: European allies strongly opposed U.S. actions, leading France to withdraw from NATO’s integrated military command.

Iraq War (2003): NATO was deeply divided, with several members refusing to participate at all.

Libya (2011): Disagreements over leadership and mission goals exposed strategic fractures.

While these disputes didn’t involve allies fighting each other directly, they weakened trust — something any military alliance relies on.

What the Greenland Debate Really Reveals

The Greenland discussion isn’t about imminent war. It’s about perception, trust, and precedent.

When even hypothetical claims over allied territory enter political discourse, they shake the assumption that NATO members will always respect each other’s sovereignty. Danish leaders have made it clear: any attempt by one ally to seize territory from another would destroy NATO’s credibility.

In an era of rising Arctic competition, resource scarcity, and shifting global power, such clarity matters.

Final Thoughts: Unity Is Not Automatic

NATO has survived for more than 75 years not because its members never disagree, but because they repeatedly choose diplomacy over escalation.

History shows that alliances don’t prevent conflict — leadership does.

The Greenland debate is a reminder that NATO’s strength lies not just in military power, but in restraint, communication, and mutual respect. The moment those weaken, even the strongest alliance can begin to fracture.