THE BUSH ADMINISTRATION CLAIMS THE authority to stop Oregon physicians from using prescription drugs to implement that state's unique program of physician-assisted suicide. But the administration's effort to use an ambiguous federal drug statute to undermine Oregon's assisted suicide law is a betrayal of conservative legal principles. Gonzales v. Oregon, argued before the Supreme Court earlier this month, may give an early signal about the commitment of the emerging Roberts Court to those principles. And the Court's decision could have unexpected implications for a range of other issues, including future policies about abortion.Like the administration, I believe that the people...