For 20 years, Mort Klein has served as National President of the Zionist Organization of America, a right-leaning Israel advocacy group with a venerable history. But on Sunday, Klein will face the first election challenge of his presidency when ZOA members meet to vote on granting him another term as Steven Goldberg challenges him for the position.

The issues at stake do not involve the group’s political direction. Both men stand firmly on the right end of the Zionist political spectrum and are, among other things, deeply suspicious of the current U.S.-brokered Middle East peace process and of the two-state solution for Israel and the Palestinians that is endorsed by Israel and the Jewish establishment.

But the contest has grown into a bitter feud following the group’s short-term loss under Klein of its tax-exempt status for failing to file tax documents with the IRS for three years, as first reported by the Forward.