A sense of greater global turmoil and internal threat led Icelandic statesmen to reconsider Iceland's security arrangements. The Czechoslovak coup d'état in February 1948 made the world seem less peaceful and made a communist coup in Iceland seem plausible. The Icelandic coalition government of the Independence Party, the centrist Progressive Party and the Social Democrats began to look for security guarantees for Iceland. Basing US military forces on Icelandic soil was considered domestically unfeasible at the time, so the options were between a Scandinavian Defence Union and NATO. When negotiations for a Scandinavian Defense Union fell apart, Iceland followed Denmark and Norway into NATO.