Iceland

During World War II, Iceland joined Denmark in asserting neutrality. After the German occupation of Denmark on 9 April 1940, the Althing replaced the King with a regent and declared that the Icelandic government should assume the control of foreign affairs and other matters previously handled by Denmark. A month later, British armed forces invaded and occupied the country, violating Icelandic neutrality. In 1941, the occupation was taken over by the United States so that Britain could use its troops elsewhere, an arrangement reluctantly agreed to by the Icelandic authorities.
• Independent republic 1944–present
On 31 December 1943, the Danish–Icelandic Act of Union expired after 25 years. Beginning on 20 May 1944, Icelanders voted in a four-day plebiscite on whether to terminate the personal union with Denmark, abolish the monarchy, and establish a republic. The vote was 97% to end the union, and 95% in favour of the new republican constitution. Iceland formally became a republic on 17 June 1944, with Sveinn Björnsson as its first president.
In 1946, the Allied occupation force left Iceland. The nation formally became a member of NATO on 30 March 1949, amid domestic controversy and riots. On 5 May 1951, a defence agreement was signed with the United States. American troops returned to Iceland as the Iceland Defence Force, and remained throughout the Cold War. The US withdrew the last of its forces on 30 September 2006.