Experts have warned that Vladimir Putin could use a NATO loophole to attack the US and not trigger Article 5.

On Sunday, December 7, 1941, the course of World War 2 changed forever when Japan launched a surprise attack on the American naval base at Pearl Harbor in Honolulu, Hawaii.

Consequently, it led then-president Franklin D. Roosevelt to join the Allies and declare war on the Axis – a move that would eventually lead to the use of nuclear weapons to force Japan into surrender.

However, experts warn that if Vladimir Putin did the same thing today, the members of the North Atlantic Treaty Organisation would not be obligated to rise to the Aloha State’s defence.

David Santoro, president of the Pacific Forum think tank in Honolulu, said:…