Arnold Eisen twice brought a room of Conservative rabbis to their feet in his inaugural address to the movement’s rabbinical association Monday. Speaking at the annual Rabbinical Assembly convention in Boston, the chancellor-elect of the Jewish Theological Seminary called for a wide discussion of the idea of mitzvah, a contentious subject for a movement dedicated to a careful balance of tradition and modernity. “I think we’ve largely dropped the ball when it comes to message,” said Eisen, who urged the movement to build tight communities and fill them with enriching content. The R.A. convention comes at a time of unease in the Conservative movement, whose legal authorities recently voted to permit gay and lesbian clergy in a move that some feared would cause an irrevocable split. Along with resolutions on the Iraq war and Darfur, there’s an effort to have the convention discuss a resolution calling on all the movement’s rabbinical schools to accept gay and lesbian students.