Roger Baldwin, 97, a founder and retired executive director of the American Civil Liberties Union, who spent his life in tenacious defense of the Bill of Rights for all Americans, died Wednesday in a hospital in Ridgewood, N.J. He had emphysema and a heart ailment.

The ACLU was founded at a meeting in New York City in 1920 called to form a "permanent, national, nonpartisan organization with the single purpose of defending the whole Bill of Rights for everybody." In addition to Mr. Baldwin, persons at the organizing session included Helen Keller, Norman Thomas, Clarence Darrow, and Felix Frankfurter.

Mr. Baldwin was the organization's executive director from 1920 to 1950, then spent five years as its national chairman. He had been the ACLU's adviser on international affairs since the 1950s.

He had been a teacher, social worker, court probation officer, and civic activist. He never graduated from law school nor held elective office, but still became a powerful voice in the evolution of American law.

He once wrote, "I call myself a political reformer, and it is about as near as I can come to describing the unclassified occupation that marks my whole public life."

The ACLU's statement of purpose said, "We stand on the general principle that all matters of public concern should be freely discussed without interference." During Mr. Baldwin's years as executive director, the ACLU defended Nazis, members of the Ku Klux Klan, Communists, and Sacco and Vanzetti.

It defended labor organizations and their right to organize on the one hand, and the right of Henry Ford to distribute antiunion leaflets on the other. They even offered to go before the FCC to defend an author, who intended to attack the ACLU as a Communist-financed organization, in her right to be heard on radio.

Mr. Baldwin said that two cases involving the ACLU, separated by 37 years, gave him the greatest personal statisfaction. One was the ACLU's defense of John Scopes, the teacher prosecuted for teaching evolution, in the so-called "Monkey Trial" in 1925, and the other was the 1962 one-man, one-vote decision of the U.S. Supreme Court.

In January 1981, President Jimmy Carter awarded Mr. Baldwin the White House Medal of Freedom for his lifelong work in behalf of civil rights. After learning of Mr. Baldwin's death, Ira Glasser, executive director of the ACLU, and Norman Dorsen, president of its board of directors, issued a joint statement, saying Mr. Baldwin "was in a way one of our country's founding fathers. They wrote the Constitution and he found a way to enforce it."

Mr. Baldwin was born into a Unitarian family in Wellesley, Mass. He once recalled, "I started my infantile social work at about 10, went to church with unquestioning belief in man, if not God, and read history outside school with a reformer's eye on the side of the underdogs and rebels. Not that I did not like our society. I did.I liked it so much that I was certain that democracy would perfect it, and that good people like us would prevail."

He was a 1904 graduate of Harvard University and earned a master's degree in anthropology there a year later. Following a tour of Europe, he went to St. Louis and taught sociology at Washington University for three years. He was chief probation officer of the St. Louis Juvenile Court from 1907 to 1910, and executive secretary of the St. Louis Civic League, a clean-government organization.

Before moving to New York about 1917, he became acquainted with anarchist Emma Goldman and read the works of anarchist Prince Peter Kropotkin. "From a domestic reformer I became almost an instant internationalist, concerned with the fate of the universe," he later recalled.

Mr. Baldwin was active in the American Union Against Militarism, and when the United States entered World War I, became a conscientious objector. His opposition to the war was based on rational rather than religious principles. He was drafted, refused induction into the Army and spent a year in jail. At his trial he said, "I know that as far as my principles are concerned, they seem to be utterly impracticable. They are not views that work in the world today. I fully realize that. But I fully realize taht they ate the views which are going to guide in the future."

After his release from prison, he rode the rails and worked in factories and brickyards before becoming the organizing force behind the ACLU. After World War II, he traveled to Japan and Germany as a War Department adviser on protection of civilian liberties in those defeated nations. In later years he taught at the University of Puerto Rico and at the New School for Social Research in New York. He was a past chairman and honorary president of the International League of Human Rights.

Mr. Baldwin's marriage of 15 years to the former Madeleine Z. Doty, a lawyer and feminist, ended in divorce in 1934. Two years later, he married Evelyn Preston, another feminist. She died in 1962.

Mr. Baldwin was a resident of Oakland, N.J. His survivors include two sons.