Change to Win, a group of unions endorsing Sen. Barack Obama (D-Ill.), is calling on Mark Penn, senior strategist to Sen. Hillary Rodham Clinton (D-N.Y.), to be removed from her presidential campaign for meeting with the Colombian ambassador about a controversial trade agreement.

Clinton has steadily railed against unfair free trade, but Penn, in his capacity as head of the lobbying firm Burson-Marsteller Worldwide, met with the ambassador to talk about the country’s trade agreement with the U.S. The Bush administration is trying to move it through Congress over Democratic opposition.

"It's time for Sen. Hillary Clinton to send her vaunted 'chief strategist' Mark Penn packing — back to his job consulting for union-busting corporations and anti-labor governments for good,” Tarpinian said in a statement.

 Penn expressed regret for the meeting as he sought to put distance between it and Clinton’s position on trade. Both Clinton and Obama have said they would vote against the Colombia trade deal.

“The meeting was an error in judgment that will not be repeated and I am sorry for it,” Penn said. “The senator's well known opposition to this trade deal is clear and was not discussed.”