Properly speaking, the movement was inaugurated at the First Zionist Congress, convened in Basle in 1897, which adapted the Basle program explicitly endorsing Theodor Herzl's political conception of Zionism. From then on Zionist history was viewed as being divided into two epochs; Hibbat Zion up to the First Congress and from then on "Zionism," i.e., political Zionism.
This did not, however, put an end to the prolonged struggle between the two concepts inside the Zionist movement, between the "political" and the "practical" Zionists, each of whom regarded their approach to the realization of the Zionist aim as the genuine meaning of the term "Zionism."
It was at the Eighth Zionist Congress (1907) that Chaim Weizmann coined a new term, "synthetic" Zionism, which stipulated that the two approaches supplement each other and are in reality two sides of the same coin: political activity is meaningless unless it is based upon practical settlement in Erez Israel, and settlement alone could not develop into desirable proportions without the support of political efforts.
Though Herzl is rightfully considered the father of Zionism, the movement had a number of forerunners in the modern period.
The rabbis Judah Alkalai (1798-1878) and Zevi Hirsch Kalischer (1795-1874) both preached a Return to Zion that had elements of a modern nationalist conception alongside the traditional messianic impulse.
Moses Hess, too, though secular in his outlook, saw in his "Rome and Jerusalem" the solution to disintegrating Jewish religious life in the reconstruction of national life in the ancient homeland.
These trends, coupled with the shock of the pogroms of 1881, gave rise to the Hibbat Zion movement in Eastern Europe, aiming at a national renaissance of the Jews and their return to Erez Israel. Ultimately, this movement merged with the Zionist Organization founded by Theodor Herzl.
In the few years that were given him at the head of Zionism, Herzl held consistently, until near the very end of his days, to the line that only the attainment of a charter, of a political document granting Jews near-sovereign rights in the territory that they were to settle, was the first objective of Zionism.
He therefore fought against turning the Zionist movement into an instrument of piecemeal settlement, and the aid that was given the early settlements in his lifetime, little though it was, was a concession that he made to his opponents in the movement, the "practical" Zionists.
He also bitterly opposed the turning of Zionism toward cultural endeavors either by linking it with the secular Hebrew revival or by coupling Zionism with the national religious orthodoxy of the Mizrachi faction which was arising near the end of his days.
Of all the schools of thought that were arising within the Zionist movement in its very first few years, Socialist Zionism was, at least in practice, the most important. For A. D. Gordon and his pioneering disciples Zionism was an act of will, an affirmation of the dignity of physical labor and the rootedness of man in his own soil, of the desperate necessity to create a new Jewish man in the Land of Israel to replace the disfigured human being who had been shaped by his misery and alienation from nature in the Diaspora. The men of the Second Aliyah, the young pioneers who went to Erez Israel in the first decade of the 20th century, adhered in their majority to some version of the socialist Zionist faith and especially to the notion that the "new man" whom they were creating and exemplifying through themselves was the essential positive feature of Jewish history in the modern era. This group was eventually to become the dominant element among the founders of the State of Israel.
The major thrust of Zionism in the era immediately after Herzl was neither toward his purely political activity for the achievement of the "charter," nor toward small-scale settlement combined with cultural evolution; it was toward the "synthetic Zionism" of Chaim Weizmann, who had succeeded to the acknowledged leadership of the movement by 1917, when the Balfour Declaration was obtained from the British Government as the result of prolonged negotiations during which he had been the central figure. Zionism was thus transformed into a mass movement and into a major political force. There was internal struggle among the various factions, but out of their interaction, a kind of consensus was achieved which became the actual premise for all Jewish political life in the next decades, the interwar years.
Meanwhile, the Zionist settlement in Palestine was increasing from roughly 60,000 in 1919 to 600,000 in the 1940s. Throughout this period, the Zionist movement was engaged in an incessant struggle with the British Mandate authorities to bring about the conditions that would make possible the creation of a Jewish state in Palestine. After much heated debate within the movement, it was decided to accept the Peel Commission's partition plan, the movement opposed unanimously the British White Paper of 1939 restricting Jewish immigration and in 1942 announced the Biltmore Program which postulated Jewish independence as the Zionist war aim.
With the establishment of the State of Israel, the Zionist Organization continued to play an important political and financial role in the world arena but clearly its primacy was overshadowed by the existence of the State of Israel itself. With the establishment of the State, Zionism as an ideological concept too has been increasingly called into question, often dismissed by young Israelis as an ossified relic of the past irrelevant to modern concerns. Yet as a force that has defined the terms of modern Jewish nationalism and whose message is relevant as long as there is a Diaspora, it remains the central ideological movement of modern Jewish history.