Supreme Court nominee David Souter, the circumspect New England jurist who during his confirmation hearings disarmed opponents and enhanced a reputation for judicial excellence, faces his final Senate test. Souter is expected to sail through full Senate confirmation proceedings, which were scheduled to start later Tuesday. The Senate Judiciary Committee approved Souter's nomination 13-1 last week. Souter, 51, a member of the 1st U.S. Circuit Court of Appeals since April and a former New Hampshire Supreme Court justice, was named by President Bush to replace Justice William Brennan, who retired in July after 34 years on the Supreme Court.