The year 1982 emerged as pivotal in the Atlantic Alliance and the relationship between President Ronald Reagan and Prime Minister Margaret Thatcher. On 6 June 1982, Israeli Defense Forces breached the Lebanese border in a maneuvre to eradicate the Palestinian Liberation Organization. The campaign opened a violent episode in the decades-old Arab-Israeli conflict. Almost immediately the British Foreign and Commonwealth Office recognized the challenge to the international community. The crisis in the Middle East occurred during a period of substantial turnover in the foreign policy communities of both London and Washington. Subsequent improved bilateral relations between the United States and the United Kingdom paved the way for greater cooperation in international diplomacy between respective national executives.