Washington, D.C. ? Former Dallas mayor Ron Kirk, apparently on course to be the next U.S. trade representative, told senators Monday that his main objective as the nation’s top trade official will be enforcing existing law and insisting that U.S. trade partners play by the rules.

He made clear that trade policy under President Barack Obama would differ from that of the Bush administration, when the emphasis was on cementing new free trade agreements.

Kirk, generally supported by the business community as an advocate of expanded trade, said he would make his top priority assuring that existing trade partners live up to the rules — in such areas as labor rights and environmental protection.

Revelations that Kirk, like other administration nominees, had tax payment problems, were barely mentioned in the abbreviated hearing of the Senate Finance Committee.