The Trump administration once again threatened to take control of Greenland by acquiring it or using military force to “deter our adversaries in the Arctic.”
Greenland, a semi-autonomous territory of Denmark, is already home to the Pitufik space base, which the United States operates in conjunction with Danish authorities. The United States and Denmark are both founding members of NATO, the most powerful military alliance.
European and Canadian leaders supported Denmark and Greenland and said they were working on plans in case the United States carried out its threats.
Analysts say the U.S. attempt to seize Greenland is an unprecedented move in NATO history and will raise serious questions about the limits of Article 5, which is meant to keep the alliance alive and protect it from external aggressors.
What happens if a NATO member attacks another NATO member?
Collective defense is a governing principle of NATO, and Article 5 of the North Atlantic Treaty provides that an armed attack against one NATO member state is considered an attack against all NATO members.
This has been a binding pledge since the alliance was formed in 1949, building solidarity between North America and Europe.
Article 5 requires the unanimous consent of all member states to trigger it, so an alliance cannot vote to start a war against itself, leading to a stalemate when a conflict arises between two member states.
Article 5 was only invoked after the September 11, 2001 attacks in the United States.
In this timeline, Al Jazeera examines the closest instances in which NATO members faced potential conflict with each other.
limited military conflict
1958–1976 – British-Icelandic fishing dispute
The Cod Wars (1958-1976) were a series of escalating conflicts between Great Britain and Iceland over fishing rights in the North Atlantic.
Although the conflict did not result in a full-scale conflict, it did spark a series of maritime collisions, including ship ramming and diplomatic tensions between NATO members.
Fearing the loss of Iceland’s Keflavik Air Base, vital for monitoring Soviet submarines in the North Atlantic, NATO and the United States pressured Britain to make concessions. The conflict ended in 1976 with an important diplomatic victory for Iceland, establishing a 200 mile (322 km) limit that remains the global standard today.
1974 – Greece and Turkiye over Cyprus
Turkey’s invasion of Cyprus in 1974 was the closest a NATO member state came to an all-out war. After a Greek-led coup in Cyprus, Turkiye launched a military intervention that nearly triggered a direct conflict between the two NATO members.
In protest of NATO’s failure to rein in Turkiye, Greece withdrew from the alliance’s military organization from 1974 to 1980.
Considering this was the Cold War era, both member states were essential to NATO’s collective front against the Soviet Union. Although there was some military action between Greece and Turkiye, the alliance was able to prevent direct war.
1995 – Canada-Spain fishing dispute
In 1995, Canada and Spain came close to a naval battle during the “Turbot War.” Canada has imposed regulations to protect fish stocks, including the turbot fish species, leading to accusations that EU fishing vessels are overfishing just outside Canada’s exclusive economic zone.
Tensions escalated after a Canadian Coast Guard vessel fired warning shots at a Spanish trawler and arrested its crew. Europe threatened sanctions, but Britain vetoed them and sided with Canada alongside Ireland. In response, Spain deployed naval patrols and Canada authorized its navy to fire on trespassing vessels, bringing NATO members dangerously close to conflict.
EU mediation ended the crisis, resulting in Canada withdrawing its enforcement measures and establishing a joint regulatory framework.
dispute over war engagements
NATO also faces internal divisions over when and how to intervene militarily, with some member states often wanting to avoid direct military action.
1956 – France, Britain, and the United States over the Suez Crisis
During the Suez Crisis of 1956, following the nationalization of the Suez Canal by Egyptian President Gamal Abdel Nasser, France and Britain formed a secret alliance with Israel to invade Egypt.
The operation caused a serious crisis within NATO, as the United States strongly opposed military action, fearing Soviet intervention and alienation of the Arab world. Despite the lack of an agreement, France and Britain continued the operation anyway.
The conflict was ultimately resolved by the United Nations Emergency Force (UNEF), the first armed peacekeeping mission in UN history, establishing a blueprint for future UN peacekeeping operations.
1960s and 1970s – US and European allies in the Vietnam War
The Vietnam War saw major disagreements among NATO members over U.S. military intervention, with the U.S. government viewing Vietnam as an important front in the Cold War, while major European allies such as France and the United Kingdom opposed direct military intervention.
France publicly condemned the war and ultimately withdrew from NATO’s military command in 1966 to avoid involvement in a future U.S. conflict. France finally rejoined the military in 2009, 43 years later.
The war was widely unpopular with the British public, and Britain opposed sending British troops despite pressure from the United States. However, it did provide logistical and intelligence support to the United States. What is interesting is that Australia committed troops to the war despite not being a NATO member, given its normally close alliance with the UK.
These differences caused tensions between NATO’s largest members and resulted in the Vietnam War not being mandated under NATO command. As a result, NATO headquarters was moved from France to Belgium, where it remains today.
1999 – Greek opposition to Kosovo air operations
In 1999, NATO launched an air operation in response to ethnic cleansing carried out by Serbian forces in Kosovo.
The alliance conducted air operations against Yugoslavia, but encountered serious reservations from NATO members such as Greece, which shared close cultural and religious ties with Serbia. Greek protesters physically blocked and targeted British troops and tanks as they moved to join coalition forces.
Greece became the first NATO member to call for an end to bombing.
2003 – European allies split over Iraq war
The 2003 Iraq War caused one of the deepest rifts in NATO’s history.
The alliance supported Security Council Resolution 1441, which gave Iraq “one last chance to comply with its disarmament obligations,” but three NATO members, France, Germany and Belgium, rejected U.S. claims that they had authorized immediate military action, resulting in a stalemate.
In the end, the invasion was carried out by a “coalition of the willing” rather than NATO itself, and Article 5 remained uninvoked.
2011 – Differences of opinion over intervention in Libya
During the 2011 intervention in Libya, NATO members could not agree on whether NATO should be responsible for enforcing a no-fly zone over Libya if the United States stepped back from leading the operation.
Germany and Poland fully opposed military intervention, and Germany refused to support a UN Security Council resolution authorizing NATO action. Mr. Tolkier also voiced strong opposition, insisting that any action must be quickly concluded to avoid occupation.
France opposed leading a NATO intervention, but Italy said it wanted to regain control of air bases it had granted to allies unless a coordination arrangement was agreed.
These internal divisions delayed NATO from assuming formal command of air operations until almost two weeks after the first Allied offensive began.
Other notable disagreements
NATO faces disagreements over its expansion into Afghanistan and Eastern Europe after the Russia-Ukraine war. Some member states restrict how and where their armed forces operate.
Additionally, there are budget disputes and missile defense issues. However, the alliance never fell apart.
What is happening now in Greenland is a test of NATO’s unity.
