From left: Mark Anderson / Rubberball / Corbis; Chris Desmond / Getty Images The U.S. Supreme Court Building, left, and a protest by the Westboro Baptist Church in 2008

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After Matthew Snyder, a U.S. Marine, was killed in Anbar province in Iraq in 2006, some uninvited guests showed up at his funeral at St. John's Catholic Church in Westminster, Md. The Rev. Fred W. Phelps Sr. of the Westboro Baptist Church and several family members came from Kansas holding signs reading "Thank God for Dead Soldiers," "God Hates Fags" and "You're Going to Hell."

There is no question it was hateful stuff. Phelps' self-styled church preaches that God is punishing America because of its tolerance for homosexuality, especially in the military. The Phelps family makes its point by holding protests at military funerals. The Phelpses also posted an "epic poem" online entitled "The Burden of Marine Lance Cpl. Matthew A. Snyder," which, among other things, says to his parents, "you raised him for the devil." (See "Should Bigoted Speech Be Free? A Debate in Britain.")

Snyder's father, Albert Snyder, sued. He said that the protests, at the funeral of his only son, made him violently ill. He prevailed on his claims of invasion of privacy and intentional infliction of emotional distress and won a large damage award, but that ruling was reversed on appeal.

Next week, the Supreme Court will hear arguments in the case. As the court begins its term  the traditional first Monday in October  the Phelps case is only one of several important ones on the docket. In Schwarzenegger v. Entertainment Merchants Association, the Justices will consider whether a California law banning the sale of violent video games to minors violates the First Amendment. In NASA v. Nelson, the court will weigh whether government workers have a constitutional right not to answer personal questions asked by their employers. There are also significant sex-discrimination and citizenship cases.

But for drama and emotion  and formidable constitutional issues  none rivals Snyder v. Phelps. Phelps is a toxic force  the Anti-Defamation League and the Southern Poverty Law Center have labeled his church a "hate group." The Snyders could hardly be more sympathetic. Albert Snyder said the Phelps protests aggravated his diabetes and his depression. He said he vomited when he read the "epic poem."

After his case went to trial, a jury awarded Albert Snyder $10.9 million in compensatory and punitive damages. The judge reduced the award but stood by the verdict. In reversing that decision, the U.S. Court of Appeals for the Fourth Circuit ruled that the church's speech was protected. Much of it involved matters of "public concern," the court said, "including the issue of homosexuals in the military" and "the political and moral conduct of the United States and its citizens." The "epic poem" did not purport to be literal facts about Matthew Snyder but rather relied on "loose, figurative or hyperbolic language." (See TIME's top 10 gratuitously provocative acts.)

There is, not surprisingly, a groundswell of support for Albert Snyder's case before the Supreme Court. Majority leader Harry Reid and minority leader Mitch McConnell and 40 other Senators  ranging from Barbara Boxer on the left to David Vitter on the right  have signed a friend-of-the court brief urging the court to reverse the decision below and reinstate the verdict against Phelps. Another brief is signed by the attorneys general of 48 states and the District of Columbia.

Albert Snyder's claim can be framed so it does not seem to intrude too far on freedom of speech. There is no need, some of his supporters say, to hold that speech like Phelps'  horrible though it is  is not protected by the First Amendment. It is enough to say that this is a special situation: that funerals are unusually private, that the death of a child in the military is uniquely worthy of respect, and that a special zone of privacy should be carved out.

It is an emotionally appealing argument  who can read these facts and not hope that Phelps is gravely punished and Albert Snyder is comforted in his loss? The trouble is, once courts begin making exceptions of this sort, the First Amendment quickly gets whittled away. There are those who argue for creating free-speech exceptions for Nazis marching through the town square or for the burning of holy books of one sort or another. Almost everyone has some kind of speech they regard as intolerable  they just do not agree on what that speech is.

It is always perilous to guess what the Supreme Court will do, but earlier this year the Justices ruled that horrific videos of animal cruelty are protected speech. That 8-1 ruling suggested that the current court is not inclined to create new categories of unprotected speech.

Even for the most committed civil libertarian, it is hard to get excited about defending a hate-spewing minimob that targets the funeral of a dead soldier or signs saying "God Hates the USA. Thank God for 9/11." Still, it is important for the court to rule that this kind of expression lies within the First Amendment. We defend it not because these ideas are particularly worthy of being protected, but because all ideas, even the most loathsome, are.

Cohen, a lawyer, is a former TIME writer and a former member of the New York Times editorial board. Case Study, his legal column for TIME.com, appears every Wednesday.

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