WASHINGTON - A Democratic senator warned CIA Director Porter Goss Thursday that his efforts to make major changes could have "a significant and negative effect on the agency." In a letter to Goss, Sen. Dianne Feinstein, D-Calif., also said she feared the "politicization of our intelligence services" because of an e-mail Goss sent this week to agency employees telling them to serve the Bush administration. Goss, former chairman of the House Intelligence Committee, took office in September and named some of his former congressional staffers to high-level positions at the agency. Several senior CIA officials have resigned in recent weeks,...