Zionism — What it is and isn’t
Historically, Zionism is a movement that began in the 19th century, a kind of patriotic awakening like that of many other national groups. Its practical realization received great impetus from European antisemitism: Zionists like Herzl believed that Jews living as minorities would always be persecuted, and that the only way they could live normal lives would be as citizens of a Jewish state, like Frenchmen or Germans in their states. Many (but not all) early Zionists believed that the Jewish state should be in the historical Jewish homeland, the land of Israel.
You can read more about the history and development of Zionism here.
What it is
Today, since the establishment of the State of Israel, Zionism has come to mean the view that the Jewish state is fully legitimate and belongs to the Jewish people; that it is in some sense the center of Jewish life (even though many Jews and even Zionists don’t live there), and that it must be protected and supported.
Zionism demands that Jews have the rights of self-determination and self-defense. It has been called the “movement of national liberation for the Jewish people” since Jews living under unfriendly regimes around the world have migrated to Israel in order to be able to exercise their basic human rights (often including the right to life).
Zionism does not specify exactly what the borders of the state should be. Zionist arguments can be made for keeping all the territories or for withdrawing to the Green Line.
Zionism does not require that civil rights of non-Jewish minorities living in Israel be limited in any way, but it does demand that the State of Israel have a Jewish character. Israel is a democratic Jewish state. Despite what anti-Zionists may say, these characteristics are not contradictory.
Zionism and Israel are under attack ideologically and physically today in a way which is almost unprecedented, due to a confluence of geopolitical and economic factors, religious issues, antisemitism, and advances in media technology.
What it isn’t
The word ‘Zionism’ is one of the most misapplied in any language. It is a magnet for antisemitic speakers and writers, who have used it to mean whatever they like in the service of their hateful agendas.
Zionism does not imply that Jews are superior to Arabs or anyone else. It does not imply that Jews have a privileged relationship to God. There are religiously observant and secular Zionists; indeed a Zionist doesn’t even have to be Jewish. It has nothing to do with racism, communism, capitalism, atheism, militarism or indeed any other ‘ism’. Zionists do not wish to conquer the world, or even the Middle East, nor do they wish to secretly control the behavior of various nations.
Zionism per se is not significantly different from the desire of other groups — the French, the Germans, even the Palestinians — to live in their own homeland. As embodied in the democratic State of Israel it is arguably more enlightened than many national ideologies.