Lawyers and judges must ensure that civil liberties are protected in the government's efforts to prevent terrorist attacks, Supreme Court Justice Stephen Breyer said Monday.

Breyer urged attorneys to question government anti-terrorism practices, including the lack of access to legal counsel for some people detained for questioning.

"The Constitution always matters, perhaps particularly so in times of emergency," Breyer told the Association of the Bar of the City of New York.

By searching for alternative methods that avoid "constitutional mistakes," lawyers, judges and security officials help the government avoid extreme positions that the Constitution doesn't matter or that security emergencies don't matter, Breyer said.

Several court cases contend the Bush administration has gone too far in the war on terror, both in tracking and locking up suspects following the Sept. 11, 2001, attacks and in denying legal representation to Afghan War fighters detained at a U.S. naval base in Cuba.

Breyer said that while the administration may claim that courts do not have jurisdiction in some of the terror cases, judges will have to make that determination.

Members of the Supreme Court are generally circumspect in commenting on politics and policy outside their formal opinions. Some do, however, occasionally try to use their public appearances to gently influence the legal system's agenda.

Breyer said that disagreements "about government restrictions, security threats, civil liberties, do not mean that disaster is upon us, but that the democratic process is at work."

Named to the court in 1994 by President Clinton, Breyer generally votes with the more liberal justices.

Susan Herman, a professor at Brooklyn Law School, said Breyer's New York trip "may be a way for him to present a different point of view" than that by Justice Sandra Day O'Connor, a moderate conservative who after the attacks predicted unprecedented restrictions on Americans' personal freedom.

Some Bush administration critics praised Breyer's speech.

"I think you have a government that's antagonistic to the Bill of Rights, and we need a bench and bar that's prepared to rein them in," said William Goodman, an attorney and former legal director for the Center for Constitutional Rights.