Politics in Israel is dominated by Zionist parties. They traditionally fall into three camps, the first two being the largest: Labor Zionism (social democrat), Revisionist Zionism (conservative) and Religious Zionism. There are also several non-Zionist Orthodox religious parties, non-Zionist left-wing groups, as well as non-Zionist and anti-Zionist Israeli Arab parties.
Golda Meir, Prime Minister of Israel from 1969 to 1974, once joked that "in Israel, there are 3 million prime ministers". The particular version of proportional representation used, in which the whole country is a single constituency, encourages the formation of a large number of political parties, many with very specialized platforms, and often advocating the tenets of particular interest-groups. The prevalent balance between the largest parties means that the smaller parties can have strong influence disproportionate to their size. Due to their ability to act as tie breakers, they often use this status to block legislation or promote their own agenda, even contrary to the manifesto of the larger party in office.
From the founding of Israel in 1948 until the election of May 1977, Israel was ruled by successive coalition governments led by the Labor Alignment (or Mapai prior to 1967). From 1967 to 1970, a national unity government included all of Israel's parties except for the two factions of the Communist Party of Israel. After the 1977 election, the Revisionist Zionist Likud bloc (then composed of Herut, the Liberals, and the smaller La'am Party) came to power, forming a coalition with the National Religious Party, Agudat Israel, and with others.