WASHINGTON, Aug. 11 - A dozen Senate Democrats suggested Wednesday that they would not oppose President Bush's nomination of Representative Porter J. Goss as director of central intelligence, but they vowed to use his confirmation hearings to amplify their concerns over fatal intelligence failures under this administration. Senator Pat Roberts, the Kansas Republican who is chairman of the Senate Select Committee on Intelligence, said he expected to open the confirmation hearings the first week of September. He also predicted that Mr. Goss, a Florida Republican, would be confirmed. In interviews, none of the Senate Democrats disputed that prediction. In fact,...