Environmental demonstrators are dogging Al Gore on the campaign trail, demanding that he act on behalf of the U’wa indigenous tribe in Colombia, whose ancestral rainforest lands are threatened by Occidental Petroleum’s plans to drill for oil. Protestors say the U’was’ rights are being violated, and point to a violent confrontation last month between U’wa villagers and police protecting the interests of Occidental, which led to at least one death. Enviros point out that Gore has close financial ties to Occidental: the veep’s family owns as much as $500,000 in Occidental stock, his father served on the company’s board, and the company is a major contributor to the Democratic Party. Three enviro groups ran a full-page ad in yesterday’s New York Times calling on Gore to protect the U’wa and their homeland. Gore has refused to talk about the issue.