U.S. Trade Rep Ron Kirk is leaving administration Posted at 05:20 PM ET, 01/22/2013 US Trade Representative Ron Kirk (Pat Sullivan - AP) As expected for a couple of months, U.S. Trade Representative Ron Kirk, announced Tuesday that he's leaving the administration at the end of February. He had told President Obama of his intentions shortly after the re-election in November. Kirk, who has headed the agency since March 2009, was elected in 1995 as the first African-American mayor of Dallas. He left that job in 2001 in an unsuccessful bid for the U.S. Senate in 2002. Kirk has also been a partner in the international law firm of Vinson & Elkins. Kirk most likely is headed for a private sector position back home in Dallas. Possible successors include Fred Hochberg, a businessman who had been acting Small Business Administration chief in the Clinton Administration and is now chairman of the Export-Import Bank; Francisco Sanchez, currently Commerce undersecretary for international trade and before that assistant secretary of transportation in the Clinton administration; and Jeff Zients, former CEO of The Advisory Board Co. and now acting director of the Office of Managment and Budget.