WASHINGTON, May 31, 2010— -- Forty-eight states and the District of Columbia are backing the family of fallen Marine Matthew Snyder in a pending U.S. Supreme Court case that could decide the constitutionality of laws restricting protests at private family funerals.
Lance Cpl. Snyder, who was deployed to Iraq in 2006, was killed just a month later in an accident. His funeral in Maryland was disrupted by demonstrators led by Kansas pastor Fred W. Phelps, yelling, among other things, that America's military is evil because it defends a country that tolerates homosexuality.
Snyder's family sued, but an appeals court said the hecklers were exercising their right to free speech.
Now, all but two state attorneys general have signed a "friend of the court" brief, to be filed tomorrow, that argues the First Amendment should not apply to some "intrusive and harassing" forms of expression.
"Funeral goers are a captive audience and they are engaged in a deeply personal and private mourning process," said Kansas Attorney General Steve Six, who drafted the brief. "The Constitution does not give the respondent the right to hijack solemn proceedings such as funerals in order to spread their hateful ideas."
The respondent, Phelps, has staged loud protests with members of his Westboro Baptist Church at military funerals around the country. He argues his signs, bearing messages such as "You're in hell" and "God hates you," are protected forms of speech.
Court observers called the near-universal state support for Snyder and funeral protest laws "exceptional" and say their brief will likely affect the justices when they weigh the case this fall. Only Maine and Virginia have withheld support for the "amicus curiae" brief.
But Phelps' supporters, including his daughter Megan Phelps, say the states' brief does not change the facts of the case or weaken their constitutional argument.
"The only way you can criminalize standing peacefully on a public sidewalk with Scriptural concepts on hotly-debated public issues is to repeal the 1st Amendment," said Phelps via Twitter.
"They're willing to sacrifice the freedoms they claim Matt Snyder fought for on the altar of shutting up our message," she tweeted. "This opposition epitomizes why the 1st Amend. was passed: corrupt gov't trying to shut up religious messages they hate."
In a separate show of support for Snyder Friday, Senate Majority Leader Harry Reid, D-Nevada, filed a "friend of the court" brief joined by 42 Senators.
Senators Support Snyder in Brief Opposing Funeral Pickets
Reid has called Phelps' demonstration at the Snyder funeral an "ugly protest" and says state and federal law should "continue to protect, as it long has, the rights of all private persons -- including the families of fallen soldiers -- to mourn their loved ones at a peaceful and solemn funeral."
The Respect for America's Fallen Heroes Act, enacted by Congress and signed by President George W. Bush in May 2006, bars protesters from the property of federal cemeteries without permission and limits the duration and location of any protest approved to be performed. More than 40 states have enacted similar laws.
"In our brief to the Supreme Court, we will be arguing in part that such laws are constitutional and should be upheld," said Six.
A summary of the brief provided to ABC News shows the states will argue that their "funeral picketing/protest" laws are constitutional because of an expected right to privacy at a burial and because mourners are a "captive audience" to their dead, leaving them little choice but be subjected to the message of protesters.
"Parents, siblings, family, close friends, and neighbors cannot be expected to skip a loved one's funeral in order to avoid the malicious and intentionally hurtful messages the Phelpses love to use to target mourners," the summary reads.
The Supreme Court agreed to hear the case earlier this year on appeal by Albert Snyder, Lance Cpl. Snyder's father.
Snyder first sued Phelps and his congregation claiming that their protest at his son's private funeral was an invasion of the family's privacy and inflicted emotional distress.
A U.S. district court ruled in Snyder's favor and awarded a judgment of $5 million. But a federal appeals court overturned that decision, finding that the protest signs weren't aimed at Snyder specifically and said the statements are "protected by the Constitution."
"We are constrained to agree that these signs are entitled to First Amendment protection," the three-judge panel wrote.
The Supreme Court will hear oral arguments in the case in October.
ABC News' Matt Loffman contributed to this report.