Founded on the heels of America's civil rights movement, the Southern Poverty Law Center burnished its name with legal wins over white-supremist groups and helped integrate institutions like the Alabama State Police.
But it has also stoked anger with the Family Research Council, a conservative Christian policy group that lashed out this week after a 28-year-old gunman stormed their downtown Washington headquarters and opened fire.
"Let me be clear that Floyd Corkins was responsible for firing the shot yesterday," said council president Tony Perkins. "But Corkins was given a license to shoot an unarmed man by organizations like the Southern Poverty Law Center that have been reckless in labeling organizations hate groups because they disagree with them on public policy."
The SPLC has listed The Family Research Council as a hate group since 2010, pointing to what it describes as its anti-gay propaganda and legislative agenda.
In 1999, an FRC analyst co-authored a document titled "Homosexual Activists Work to Normalize Sex With Boys," according to the law center.
The booklet, which is not available on the FRC website, reportedly argued that "the primary goals of the homosexual rights movement is to abolish all age of consent laws and to eventually recognize pedophiles as the 'prophets' of a new sexual order," according to the SPLC.
The group opposes same-sex marriage and lobbied to prevent the repeal of the "don't ask, don't tell" policy, which prohibited military service by openly gay men and women.
Perkins said the SPLC "should be held accountable for their reckless use of terminology that is leading to the intimidation and what the FBI here has categorized as an act of domestic terrorism."
The gunman apparently said, "I don't like your politics" during the incident, and had been carrying 15 Chick-fil-A sandwiches, a possible connection to the restaurant chain's CEO and his stance against gay marriage.
Corkins, a former George Mason University student, had reportedly worked as a volunteer at an organization serving the lesbian, gay, bisexual and transgender communities.