JERUSALEM – Israeli Defense Minister Ehud Barak abruptly quit politics Monday, potentially robbing Prime Minister Benjamin Netanyahu of a key ally who enabled his hardline government to present a moderate face to the world.

Barring another comeback by the mercurial former general, Barak's departure marked an end to a distinguished and tumultuous career that spanned half a century. It began on a communal farm, led to military greatness and business success and a mixed record in politics that was highlighted by failed peacemaking efforts during a brief term as prime minister.

Despite polls showing his small centrist Independence Party gaining momentum following the eight-day Israeli offensive in Gaza that he steered, Barak said he would not run again for office in the Jan. 22 elections.