Sen. Joseph Lieberman, I-Conn., is prominent among Republicans and Democrats who are trying to form a centrist group under the banner "No Labels." Sen. Lieberman has spent years cultivating a moderate image, but his constituents know him as a political chameleon. He's reliable on national defense and foreign policy, but on domestic issues, he's on the side his polling or ambition places him: He was for school vouchers and an avowed enemy of Hollywood sleaze as a senator from flinty Connecticut, but as Al Gore's running mate in 2000, he opposed school choice and went to Hollywood, hat in hand,...