Brandon Marshall Takes a Knee for National Anthem Ahead of NFL Opening Game

The recently departed Muhammad Ali put his boxing career in jeopardy by refusing to fight in the Vietnam War. "My conscience won't let me go shoot my brother, or some darker people, or some poor hungry people in the mud for big powerful America," he said. The legal battle Ali then faced meant that he did not compete from March 1967 to October 1970, during the prime of his career.

Jane Fonda has long been a controversial figure among Vietnam War veterans. During a visit to Hanoi, a picture of her atop a Vietnamese anti-aircraft gun led to outraged Americans calling her "Hanoi Jane." Years later, Fonda apologized, saying she was manipulated into sitting with the gun and that she also regretted claiming that POWs' accounts of torture behind enemy lines were lies. 

Charlie Chaplin was accused of being a communist after he attacked capitalism and nuclear weapons in his film "Monsieur Verdoux" and publicly spoke against the Red Scare. After visiting London in 1952, he was denied re-entry to the U.S. unless he answered questions about his political views. Disillusioned with America, Chaplin chose to stay in Europe for the next 20 years, only returning to America to receive an honorary Oscar for his work.

Another star affected by the Red Scare was Lucille Ball, who was questioned about her identification as a Communist on her 1936 voter registration form. Ball said in sealed testimony to the House Committee of Un-American Activities that she only did this to appease her grandfather, who was a socialist. Before a taping of "I Love Lucy," Ball's husband and co-star Desi Arnaz famously said, "The only thing red about Lucy is her hair, and even that is not legitimate."

No one in Hollywood suffered more from the Red Scare than the Hollywood Ten, led by Oscar-winning writer Dalton Trumbo. This was a group of writers and directors who refused to testify before the HUAC, resulting in them being blacklisted from the film industry. The writers continued producing scripts under other authors' names, including Trumbo, who produced two Oscar-winning screenplays while on the blacklist: "Roman Holiday" and "The Brave One."

Musician Harry Belafonte was also blacklisted by the Red Scare, but for different reasons. Belafonte was a leading figure in the Civil Rights movement, working closely with Martin Luther King, Jr. After that era, Belafonte continued taking controversial stands against U.S. policy, including opposition to the embargo on Cuba and support of Venezuela President Hugo Chavez. His most infamous moment was in 2002, when he compared Colin Powell to a plantation house slave in the lead-up to the Iraq War.

Another loud opponent of the Iraq War and the Bush Administration were the Dixie Chicks, who faced massive backlash from country fans when they said they were "ashamed the President of the United States is from Texas" during a 2003 concert in London. Their new album plummeted out of the Billboard charts, and the band was loudly booed at that year's Academy of Country Music Awards.

After the release of Clint Eastwood's "American Sniper," Seth Rogen compared the film on Twitter to the Nazi propaganda film from Quentin Tarantino's "Inglourious Basterds." Conservatives bashed Rogen, claiming his tweets disrespected the film's subject, deceased Navy SEAL sniper Chris Kyle. Rogen later explained that he liked "American Sniper," but that certain scenes reminded him of Tarantino's film.

Martin Sheen may have played the President on "The West Wing," but after speaking out against the Iraq War, he became the target of a hate mail campaign, leading to the Screen Actors Guild making a statement in support of his right to free speech. Sheen told The Los Angeles Times that NBC had received phone calls demanding that he be kicked off of "The West Wing," and that executives asked him to tone down his criticism for fear of losing advertisers.

Michael Moore has built his career making documentaries that have criticized how America does its business, from foreign policy in "Fahrenheit 9/11" to healthcare issues in "Sicko." He's become such a polarizing figure that in 2008, "Airplane!" director David Zucker used a caricature of him as the core of his film "An American Carol," a panned comedy that depicted Moore promoting a film called "Die You American Pigs."

San Francisco 49ers quarterback Colin Kaepernick incited outrage from many fans, as well as some NFL officials, when he decided not to stand for the national anthem during a preseason game in 2016. He justified his protest by saying he won’t "show pride in a flag for a country that oppresses black people."