Once again by the Trump administration threatened Taking control of Greenland or using military force to “prevent our enemies in the Arctic region”.
Greenland, which is a semi-autonomous region of Denmark, is already the host Pitfic Space Basewhich operates in coordination with the US Danish authorities. Both the US and Denmark are founding members of the most powerful military alliance, NATO.
European and Canadian leaders have taken the plunge Support Denmark and Greenland say they are working on a plan in case the United States follows through with its threats.
Analysts say any US attempt to seize Greenland would be an unprecedented step in NATO’s history and raise serious questions about the alliance’s existence and the limits of Article 5, which is designed to defend against external aggression.
What happens if one NATO member attacks another?
Collective defense is a governing principle of NATO, where Article 5 of the North Atlantic Treaty states that an armed attack against one member of NATO is considered an attack against all.
It has been a binding pledge since 1949, when the alliance came together and which created unity in North America and Europe.
Because Article 5 requires unanimous consent from all members, a conflict between two members would create a stalemate, as the alliance could not vote to go to war against itself.
Article 5 was enacted after the September 11, 2001 attacks in the US.
In this timeline, Al Jazeera examines the near future when NATO members face potential conflict with each other.
Limited military conflict
1958-1976 – UK and Iceland fishing dispute
The Cod Wars (1958–1976) were a series of disputes between the UK and Iceland over North Atlantic fishing rights.
Although the conflict never became a full-scale conflict, it involved a series of naval clashes, including naval and diplomatic friction between the two NATO members.
NATO and the US pressured the UK to agree, fearing the loss of the Keflavík airbase in Iceland, which was needed to monitor Soviet submarines in the North Atlantic Ocean. The dispute ended in a major diplomatic victory for Iceland in 1976, establishing the 200 mile (322 km) limit that remains the world standard today.
1974 – Cyprus by Greece and Turkey
The Turkish invasion of Cyprus in 1974 is the closest NATO has come to its members engaging in full-scale war. Following a Greek-sponsored coup in Cyprus, Turkey launched a military intervention that almost led to direct conflict between the two NATO members.
In protest at NATO’s failure to deter Turkey, Greece withdrew from the alliance’s military structure from 1974 to 1980.
Given that this was during the Cold War, both members were essential to NATO’s collective front against the Soviet Union. Despite some military action between Greece and the Turks, the alliance was able to avoid outright war.
1995 – Canada and Spain have a fishing dispute
In 1995, Canada and Spain came close to a naval conflict during the “Turbot War”. Canada imposed restrictions to protect fish stocks, including a species of fish called turbot, which led to accusations that EU boats were overfishing outside Canada’s exclusive economic zone.
Tensions escalated after Canadian coast guard ships fired warning shots at the Spanish trawler and arrested its crew. Europe threatened sanctions, but the UK vetoed them with Ireland on Canada’s side. In response, Spain deployed naval patrols and Canada authorized its navy to open fire on trespassing ships, bringing NATO members dangerously close to conflict.
The crisis ended after EU mediation, resulting in Canada withdrawing its enforcement actions and establishing a joint regulatory framework.
Controversy over engagement in war
NATO has also faced internal divisions over when and how to engage militarily, with some members often seeking to avoid direct military action.
1956 – France, UK and US over the Suez crisis
During the Suez Crisis of 1956, France and Britain formed a secret alliance with Israel to invade Egypt after Egyptian President Gamal Abdel Nasser nationalized the Suez Canal.
The operation caused a serious crisis within NATO, as the United States, fearing Soviet intervention and the isolation of the Arab world, strongly opposed military action. Despite the lack of agreement, France and the UK continued operations anyway.
The conflict was finally resolved by the United Nations Emergency Force (UNEF), the first armed UN peacekeeping mission, which established the blueprint for future UN peacekeeping operations.
1960-1970 – US and European allies in the Vietnam War
US military intervention in the Vietnam War saw significant differences among NATO members, where Washington viewed Vietnam as a key front in the Cold War, but major European allies such as France and the UK opposed direct military involvement.
France openly condemned the war and relinquished military command of NATO in 1966 to avoid being drawn into future US conflicts. France finally rejoined the military structure in 2009 after 43 years.
The UK resisted sending British troops despite American pressure, as the war was widely unpopular with the British public. However, it provided logistical and intelligence support to the US. Interestingly, given its usual close friendship with the UK and despite not being a member of NATO, Australia sent troops to the war.
These differences led to tensions among the biggest players in NATO and resulted in the Vietnam War not being mandated under NATO mandate. As a result, NATO’s headquarters was moved from France to Belgium, where it remains today.
1999 – Greece opposes the Kosovo air campaign
In 1999, NATO launched an air campaign in Kosovo in response to ethnic cleansing by Serbian forces.
The alliance conducted an air campaign against Yugoslavia, but met serious reservations from NATO members such as Greece, which shared close cultural and religious ties with Serbia. Greek protesters physically intercepted and targeted British troops and tanks traveling to join Allied forces.
Greece became the first NATO member to call for an end to the bombing.
2003 – European allies split over the Iraq War
The 2003 Iraq War led to the deepest split in NATO’s history.
The alliance supported UNSC Resolution 1441, which gave Iraq “a final opportunity to comply with its disarmament obligations”, three NATO members: France, Germany and Belgium rejected US claims that they authorized immediate military action, leading to a deadlock.
In the end, the invasion was carried out by the “Coalition of the Willing” rather than NATO, and Article 5 remained open.
2011 – Disagreement over Libya intervention
During the 2011 intervention in Libya, NATO members did not agree on whether NATO should be in charge of enforcing a no-fly zone over Libya if the US withdrew from leading the operation.
Germany and Poland strongly opposed military intervention, with Germany refusing to support a UN Security Council resolution authorizing NATO action. The Turks also protested strongly and insisted that any action should avoid occupation and be concluded quickly.
France opposed NATO intervention, while Italy said it wanted to take back control of airbases authorized for use by the Allies unless a coordination structure was agreed.
These internal divisions delayed NATO taking formal command of the air campaign for about two weeks after the initial coalition strikes.
Other significant differences
NATO has faced disagreements over its deployment in Afghanistan and Eastern Europe since the Russia-Ukraine war. Some members have limited how and where their military forces can operate.
In addition, there are also budget disputes and missile defense issues. However, the alliance was never broken.
What happens now in Greenland is a test of NATO’s unity.