Initially, he drafted a pamphlet that framed Dreyfus's trial not as a simple miscarriage of justice, but the action of a specifically anti-Semitic conspiracy.
He began publishing more strident defenses of Jewish people in Parisian newspapers, and, after calling him out by name in Le Voltaire, even fought a duel with his former colleague, anti-Semitic extremist Édouard Drumont.
This tactic conformed more to the wishes of the Dreyfus family, as the first version of the text was a savage attack on the accusers, ending with repeated use of the phrase "J'accuse", later made famous by Émile Zola.
[5] Despite the change in focus away from anti-Semitism, the pamphlet still argued that this was not simply a judicial mistake, but a deliberate act to frame an innocent man.
"[9] Inspired by his experience with antisemitism during the Dreyfus Affair, Lazare became engaged in the struggle for the emancipation of Jews, and was triumphally received at the First Zionist Congress.
Lazare's Zionism was not nationalist, nor advocated the creation of a state, but was rather an ideal of emancipation and of collective organization of the Jewish proletarians.
He also visited Russia where he reported on the dangers facing Jews, but did not have a chance to publish due to illness; and Turkey where he defended the Armenians against persecution.