Four [US] senators have written to U.S. Trade Representative Ron Kirk, criticizing what they understand is a push by Chevron Corp to cut trade benefits for Ecuador, where the oil company faces a $27 billion claim in court. "We request that you allow the legal proceedings in Ecuador to take their course without any undue intervention from the U.S. government," the senators' letter said. A ruling in the long-running case…has been expected some time this year, but the company has argued that public criticism of Chevron by Ecuador President Rafael Correa makes a fair trial impossible…"Corporate responsibility at home and abroad is critical, particularly when it concerns human health and the environment," the senators' letter said.