U.S. Trade Rep. Kirk to step down in February U.S. Trade Representative Ron Kirk, who worked to get trade agreements with South Korea, Colombia and Panama through Congress, is leaving the Obama administration next month. Kirk, a former mayor of Dallas, had served as the administration's top trade negotiator through President Obama's first term in office. In a statement, Obama praised Kirk for cracking down on unfair trade practices by other countries. Kirk is the latest member of Obama's economic team to announce his departure. Treasury Secretary Timothy Geithner and Labor Secretary Hilda Solis have also announced they are leaving. The president has nominated Jacob Lew to replace Geithner at Treasury.