Revisionist Zionism is a form of Zionism characterized by territorial maximalism. Revisionist Zionism promoted expansionism and the establishment of a Jewish majority on both sides of the Jordan River. Developed by Ze'ev Jabotinsky in the 1920s, this ideology advocated a "revision" of the "practical Zionism" of David Ben-Gurion and Chaim Weizmann which was focused on the settling of Eretz Yisrael (Land of Israel) by independent individuals. Differing from other types of Zionism, Revisionists insisted upon the Jewish right to sovereignty over the whole of Eretz Yisrael, including Mandatory Palestine and Transjordan. It was the main ideological opponent to the dominant socialist Labor Zionism. Revisionist Zionism has strongly influenced modern right-wing Israeli parties, principally Herut and its successor Likud.
In 1935, after the Zionist Executive rejected Jabotinsky's political program, Jabotinsky resigned from the World Zionist Organization and founded the New Zionist Organization (NZO), known in Hebrew as Tzakh. Its aim was to conduct independent political activity for free immigration and the establishment of a Jewish State. In its early years under Jabotinsky's leadership, Revisionist Zionism was focused on gaining support from Britain for settlement. From the early 1930s, Jabotinsky believed that the United Kingdom could no longer be trusted to advance the Zionist cause, leading to a short-lived alliance with Italy.