BOSTON (AP) -- California billionaire Thomas Steyer’s threat to launch negative attacks against U.S. Senate candidate Stephen Lynch if the Massachusetts congressman doesn’t reverse his position on the Keystone XL Pipeline came under renewed criticism Wednesday from Lynch’s campaign as well as that of his Democratic rival.
Steyer, an environmental activist and longtime Democratic donor, issued the ultimatum to Lynch in a letter this week. He said if Lynch did not denounce Keystone by Friday, he would begin an "aggressive public education campaign" against the South Boston Democrat.
Lynch supports the proposed $7 billion pipeline, while U.S. Rep. Edward Markey opposes it.
The two are seeking the Democratic nomination to run in the special election for the Senate seat formerly held by Secretary of State John Kerry.
Critics of the pipeline that would run from western Canada to Texas say it would carry "dirty oil" that contributes to global warming.
Scott Ferson, a senior campaign adviser to Lynch, lashed out at Steyer on Wednesday, noting that Farallon Capital Management, the investment firm Steyer founded, purchased shares of BP after the disastrous 2010 oil spill in the Gulf of Mexico and owned $40 million in the company’s stock at the end of last year.
The Markey campaign said Wednesday it rejected the threats made against Lynch if he did not change his position on Keystone, suggesting the attacks could violate the spirit of an agreement between the two candidates that discourages advertising by outside groups.