Which American rabbi founded the Reconstructionist movement and was Judith Kaplan’s father?

Mordecai Kaplan founded the Reconstructionist movement and was Judith Kaplan’s father.

Kaplan was born in 1881 in Švenčionys, then part of the Russian Empire, and became an influential American rabbi, theologian, and educator. He developed the idea that Judaism should be understood as the evolving religious civilization of the Jewish people rather than only as a system of supernatural belief or legal observance.

His daughter Judith Kaplan became widely known for the first publicly recognized American bat mitzvah, held at the Society for the Advancement of Judaism in New York City in 1922. Kaplan’s ideas and institutional work helped create the setting in which that ceremony could be accepted and publicized.

The Reconstructionist movement later became an organized branch of American Judaism. Kaplan’s writings, including Judaism as a Civilization, shaped debates about Jewish identity, community, ritual, and modernity. He is sometimes confused with Mordecai M. Kaplan’s contemporaries such as Abraham Joshua Heschel, but they represented different theological approaches.