The American Civil Liberties Union is one of the most famous civil-rights organizations in the U.S., defending First Amendment freedoms for everyone, regardless of their views. Here are nine things you might not know about the almost century-old organization.

1. IT’S ACTUALLY TWO NONPROFITS.

There are two arms of the ACLU. The ACLU itself is a 501(c)(4) corporation, meaning that it is a membership organization that participates in lobbying state and federal government. Because of its lobbying status, you can’t take a tax deduction for your donations to the ACLU. But the ACLU Foundation is a 501(c)(3) organization, just like most nonprofits. Those tax-deductible donations go only toward funding litigation and education programs.

2. IT WAS FOUNDED TO SUPPORT CONSCIENTIOUS OBJECTORS.

Created as the Civil Liberties Bureau after World War I broke out in 1917, the ACLU was founded to, in part, oppose the creation of a draft and protect conscientious objectors to World War I, who at the time were subject to routine harassment and restrictions on what they could say for their choice to avoid service. It was initially a committee within the American Union Against Militarism, but split off due to disagreements about the organization’s vocal opposition to the government’s war policies. Then called the National Civil Liberties Bureau, it lobbied for conscientious objectors to be protected in the Selective Service Act and advised men worried about the draft. It was reorganized as the American Civil Liberties Union in 1920.

3. MANY OF ITS LAWYERS ARE VOLUNTEERS

While the ACLU does have a full-time legal staff, it relies heavily on the work of volunteer attorneys. These “cooperating attorneys” analyze proposed legislation for civil liberties issues and write commentary and complaints to government administrations and officials. As former ACLU legal director Burt Neuborne points out in a 2006 article, “one of the unparalleled strengths of the organization is the ability to mobilize literally thousands of volunteer lawyers in defense of the Bill of Rights" [PDF].

4. THE NEW YORK TIMES WAS NOT INITIALLY A FAN …

On July 4, 1917, the paper ran an editorial called “Jails Are Waiting for Them” arguing that “sensible people of good will do not make the mistake of believing that speech can be literally and completely free in any civilized country.” The author argued that “inevitably there must be restrictions on speech,” and accused the “little group of malcontents” of “antagonizing the settled policies of our Government, of resisting the execution of its deliberately formed plans, and of gaining for themselves immunity from the application of laws to which good citizens willingly submit as essential to the national existence and welfare.”

5. … NOR WAS PRESIDENT WOODROW WILSON.

Woodrow Wilson was adamant that free speech didn’t always apply during a war. Arguing for a censorship provision in the Espionage Act of 1917, Wilson wrote to a member of Congress that censorship is “absolutely necessary to the public safety.” The provision didn’t make it into the law (although in 1918 the Sedition Act was added to the same effect), but that didn’t stop the federal government from suppressing some of the activities of the National Civil Liberties Bureau. Though relations between the group and Wilson’s administration were initially friendly, in July 1917, the U.S. Postal Service banned 12 of the NCLB’s pamphlets promoting civil liberties from being sent in the mail. In 1918, the Wilson administration found the bureau’s work in violation of the Espionage Act because it encouraged men to refuse to participate in the draft, and its office was later raided by the Justice Department.

6. ONE OF ITS EARLIEST CASES IS ALSO ONE OF ITS MOST LEGENDARY.

The ACLU was the main driver behind the Scopes Monkey Trial, the landmark case that debated whether a teacher could defy state legislation banning the theory of evolution from public school curriculums. The case was actually a bit of a publicity stunt for the town of Dayton, Tennessee. The ACLU had placed an advertisement in the Chattanooga Daily Times offering to finance a case to challenge the law, which had been passed in 1925. Hoping to bring some fame and fortune to their town, Dayton's leaders immediately gathered to find a suitable teacher for the role. They ended up choosing the 24-year-old John Scopes, who hadn’t actually taught biology (he was new to teaching, and taught math, physics, and chemistry his first year). He didn’t recall teaching evolution at all, in fact, but he agreed to participate anyway, and he was arrested a few days later, with ACLU member Clarence Darrow serving as his lawyer. The trial lasted just eight days, and the jury deliberated for less than nine minutes; Scopes was found guilty and fined $100.

The ACLU planned to take the case to the U.S. Supreme Court, but the verdict was later reversed due to a technicality. According to the ACLU, "the ultimate result of the trial was pronounced and far-reaching: the Butler Act was never again enforced and over the next two years, laws prohibiting the teaching of evolution were defeated in 22 states."

7. IT’S A REGULAR FIXTURE AT THE SUPREME COURT.

The ACLU participates in more Supreme Court cases than any other private organization. ACLU lawyers represented the petitioner in the 1944 case on Japanese internment camps, Korematsu v. United States, and Mildred and Richard Loving, the interracial couple at the heart of Loving v. Virginia. The organization also regularly files amicus briefs, which are written arguments submitted to the court by someone who has an interest in the case and wants to influence the ruling but isn’t directly involved. The ACLU has filed amicus briefs in landmark cases like Brown v. Board of Education and Miranda v. Arizona.

8. ITS CLIENTS AREN’T ALWAYS LIKEABLE.

The ACLU’s crusade for freedom of speech extends to the full political spectrum—even causes that might be morally abhorrent to some of the organization’s liberal supporters. In 1978, it famously represented a Nazi group that wanted to hold a march in the heavily Jewish town of Skokie, Illinois, which included a large population of Holocaust survivors. Some ACLU members resigned over that choice, but the organization as a whole held that the principle at stake was still free speech. The case went all the way to the Supreme Court.

It has since also defended Confederate flags on license plates, online writing by NAMBLA members, the Westboro Baptist Church’s right to picket military funerals, and the Ku Klux Klan’s right to adopt a highway.

“Historically, the people whose opinions are the most controversial or extreme are the people whose rights are most often threatened,” the organization explains on its website. “Once the government has the power to violate one person’s rights, it can use that power against everyone. We work to stop the erosion of civil liberties before it’s too late.”

9. IT WASN’T IMMUNE TO THE RED SCARE

While defending Communists was a major part of the ACLU’s work in the early 20th century—it was accused of being a Communist front by the House Un-American Activities Committee—it was not entirely immune to the Red Scare’s influence. It banned Communists from serving on its board of directors in 1940, along with any other member of a “political organization which supports totalitarian dictatorship in any country.”

With that decree, it booted one of its founders, Elizabeth Gurley Flynn, who was publicly a member of the Communist Party, from the organization. It repealed her expulsion 36 years later, a dozen years after her death.

“Much of the internal rhetoric that surrounded the ACLU's deeply principled, but controversial, decision to defend the Nazi Party's right to march in Skokie, Illinois was driven by a fear of repeating the 1940 betrayal of principle,” Burt Neuborne wrote in his history of Flynn's ouster [PDF].