Herut (Hebrew: חֵרוּת, lit. 'Freedom') was the major right-wing nationalist political party in Israel. It was founded by Menachem Begin on 15 June 1948 as the political successor to the Irgun, a Revisionist Zionist paramilitary organization in Mandatory Palestine, and formally merged into Likud in 1988. Herut was highly controversial in its early years due to its Irgun origins and maximalist territorial claims, including support for Israeli sovereignty over both banks of the Jordan River. During Begin's first visit to the United States in December 1948, an open letter in The New York Times signed by Albert Einstein, Hannah Arendt and other Jewish intellectuals condemned Herut and described its organization, methods and political philosophy as "closely akin" to those of Nazi and fascist parties. In Israel, David Ben-Gurion and the ruling Labor Zionist establishment excluded Herut from governing coalitions for nearly two decades. Herut gradually moved into the political mainstream after forming the Gahal alliance with the Liberal Party in 1965 and joining a national unity government during the Six-Day War in 1967. In 1973, Gahal became the central component of Likud, which won the 1977 election and brought Begin to power, ending the long dominance of Mapai and its successor, the Alignment. Herut remained Likud's dominant faction until Likud became a unitary party in 1988.