Answer the question at the end by quoting:

Leonard Bernstein ( BURN-styne; August 25, 1918 - October 14, 1990) was an American composer, conductor, author, music lecturer, and pianist. He was among the first conductors born and educated in the US to receive worldwide acclaim. According to music critic Donal Henahan, he was "one of the most prodigiously talented and successful musicians in American history."
While Bernstein was very well known for his music compositions and conducting, he was also known for his outspoken political views and his strong desire to further social change. His first aspirations for social change were made apparent in his producing (as a student) a recently banned opera, The Cradle Will Rock, by Marc Blitzstein, about the disparity between the working and upper class. His first opera, Trouble in Tahiti, was dedicated to Blitzstein and has a strong social theme, criticizing American civilization and suburban upper-class life in particular. As he went on in his career Bernstein would go on to fight for everything from the influences of "American Music" to the disarming of western nuclear weapons.  Like many of his friends and colleagues, Bernstein had been involved in various left wing causes and organizations since the 1940s. He was blacklisted by the US State Department and CBS in the early 1950s, but unlike others his career was not greatly affected, and he was never required to testify before the House Un-American Activities Committee. His political life received substantial press coverage though in 1970, due to a gathering hosted at his Manhattan apartment on January 14, 1970. Bernstein and his wife held the event seeking to raise awareness and money for the defense of several members of the Black Panther Party against a variety of charges. The New York Times initially covered the gathering as a lifestyle item, but later posted an editorial harshly unfavorable to Bernstein following generally negative reaction to the widely publicized story. This reaction culminated in June 1970 with the appearance of "Radical Chic: That Party at Lenny's", an essay by satirist Tom Wolfe featured on the cover of the magazine New York. The article contrasted the Bernsteins' comfortable lifestyle in one of the world's most expensive neighborhoods with the anti-establishment politics of the Black Panthers. It led to the popularization of "radical chic" as a critical term. Both Bernstein and his wife Felicia responded to the criticism, arguing that they were motivated not by a shallow desire to express fashionable sympathy but by their concern for civil liberties.  Bernstein was named in the book Red Channels: The Report of Communist Influence in Radio and Television (1950) as a Communist along with Aaron Copland, Lena Horne, Pete Seeger, Artie Shaw and other prominent figures of the performing arts. Red Channels was issued by the right-wing journal Counterattack and was edited by Vincent Hartnett, who was later found to have libeled and defamed the noted radio personality John Henry Faulk.

How was he involved in activism?

he was also known for his outspoken political views and his strong desire to further social change.

IN: Aaron Charles Carter was born on December 7, 1987, at the Tampa General Hospital in Tampa, Florida, where his parents, Jane Elizabeth (nee Spaulding) and Robert Gene Carter (1952-2017), ran the Garden Villa Retirement Home. The family was originally from New York City, where his older brother Nick, of the boy band Backstreet Boys, was born. In addition to his brother Nick, he also has three sisters: twin sister Angel (a model), B.J. and Leslie (1986-2012). Carter is named after his paternal grandfather, Aaron Charles Carter, and his maternal grandfather, Douglas "Charles" Spaulding.

Carter's next album, Another Earthquake!, was released on September 3, 2002, during the "Rock, Rap, and Retro" tour. The album featured the patriotic-themed "America A.O." and the ballad "Do You Remember". He guest starred on three episodes of the Nickelodeon TV show, All That and sang the theme song to the PBS animated series Liberty's Kids, titled "Through my own Eyes."  During that time, Carter's parents filed a lawsuit against his former manager, Lou Pearlman (now deceased), in 2002 alleging failure to pay hundreds of thousands of dollars in royalties on Carter's 1998 album, which was released through Pearlman's label and production company, Trans Continental. On March 13, 2003, Pearlman was declared in contempt of court for ignoring a court order to produce documents relating to royalty payments.  Carter had also dated Lindsay Lohan along with his girlfriend Hilary Duff at the same time (leading to a feud between the two), but he broke up with Lohan in April 2003, and resumed dating Duff. Later, that same year, he reportedly cheated on her and Duff ended their on-and-off relationship after two years. Carter's Most Requested Hits, a collection including tracks from his last three albums as well as a new single, "One Better", was released on November 3, 2003.  "Saturday Night", which was released on March 22, 2005 and was promoted by Carter during his summer 2005 Remix Tour. The song was released by Trans Continental label, with Lou Pearlman as executive producer. The single was also featured in the soundtrack of the film Popstar, in which Carter starred. The direct-to-video film was based heavily on his own life as a performer. A real-life motocross racer, Carter also appeared in 2005's Supercross. On March 21, 2006, Trans Continental filed a lawsuit against Carter within the Los Angeles Superior Court, citing that Carter allegedly reneged on a recording deal. Carter had signed the contract on December 7, 2004, when he was 17 and underage. His attorney however stated that Carter had the right to "cancel or void various agreements" that were signed when he was a minor.  Carter and his siblings starred in a reality show, House of Carters, which ran in October-November 2006 on E!. The series features all five Carter siblings reuniting to live in the same house. On September 18, 2006, it was reported that Carter was engaged to former beauty queen and Playboy model Kari Ann Peniche. US Weekly later reported that Carter had broken off his engagement to Peniche, saying he was impulsive in proposing to her.

What happened with the lawsuit?

OUT:
On March 13, 2003, Pearlman was declared in contempt of court for ignoring a court order to produce documents relating to royalty payments.