The Supreme Court heard arguments Wednesday in a case that sorely tests the principle, articulated by Justice Oliver Wendell Holmes Jr. nearly a century ago, that "we should be eternally vigilant against attempts to check the expression of opinions that we loathe."

The case involves the Westboro Baptist Church, a deranged anti-gay religious group that routinely shows up at the funerals of American soldiers to express its bizarre belief that U.S. combat deaths are divine retribution for America’s tolerance of homosexuality. In 2006, the group picketed the funeral of Lance Cpl. Matthew A. Snyder, a Marine killed in Iraq. The protesters held signs reading "Thank God for Dead Soldiers," "You’re Going to Hell’ and "Semper fi Fags."

Snyder’s father sued the church for "intentional infliction of emotional distress" and other civil wrongs, but a lower court held that the picketers were protected under the First Amendment. The Supreme Court is now being asked to reverse that decision.