More than 50 members of Congress went on expenses-paid trips to Colombia; the Colombian president visited Washington to personally lobby; and companies including Wal-Mart Stores Inc. and Citigroup Inc. are backing the effort, the Times said.In addition to Burson-Marsteller — the firm run by Mark Penn, adviser to presidential candidate Hillary Clinton who was demoted over advocating to the trade deal she opposes — the Colombian government hired Glover Park Group, established by former Clinton White House aides, and Johnson, Madigan, Peck, Boland & Stewart, the Times said.