In America, April 15 is known as Tax Day. In America's national pastime, it's Jackie Robinson Day.

In this current sports era—a historic moment filled with protests and calls for athletes to "shut up and dribble," it is especially important to remember the Jackie Robinson who was determined to use his platform to fight for civil rights. And the Jackie Robinson who embodied the message, "A life is not important, except in the impact it has on other lives."

Some black-and-white photos and cinematic scenes from 42, starring Chadwick Boseman (T'Challa himself) as Robinson, lead us to believe Jackie was a mild-mannered character who quietly tipped his hat to crowds yelling racial slurs at him—because for the early part of his career, he had to.

"They're waiting for you in the jungles, black boy!" and "Hey snowflake, which one of those white boys' wives are you dating tonight?" Phillies manager Ben Chapman jeered, per Robinson's autobiography, I Never Had It Made. Confrontations like these caused Robinson to bury his hostility and go home to his wife, Rachel, "tense and irritable, keyed up because [he] hadn't been able to speak out."

Robinson wrote in the book that he was always careful about being publicly critical, because he knew "the minute I began to answer, to argue, to protest—the minute I began to sound off—I became a swellhead, a wise guy, an 'uppity' n----r. When a white player did it, he had spirit. When a black player did it, he was 'ungrateful,' an upstart, a sorehead."

This wasn't easy for Robinson, "a black man who never tolerated affronts to his dignity" prior to the major leagues. Not because Robinson wanted to get revenge, but because, as he later acknowledged, "I wanted to be Jackie Robinson," the more authentic Robinson who emerged in the 1949 season.

Rachel Robinson said his shift in attitude wasn't tied to any pledge, but to Jackie's confidence in his standing and in the integration of MLB.

"He had purchased the right to speak his mind many times over," President Barack Obama said in Ken Burns' 2016 documentary Jackie Robinson.

Robinson became more vocal regarding off-field issues like juvenile justice, communism and police brutality in African American communities.

He used his platform to advocate for black youth on the issue of juvenile delinquency. He hosted numerous sports camps at the Harlem YMCA, wrote various New York Post and New York Amsterdam News columns on the problem of youth crime and regularly called on athletes and celebrities to be more involved with organizations seeking to steer kids down the right path.

In 1959, he started a program, Athletes for Juvenile Decency, that connected professional athletes with young adults in schools, settlement and youth houses, Police Athletic League and Catholic Youth Organization groups, the YMCA and others.

And though the organizations Robinson worked closely with targeted kids of all races and ethnicities, he made no apologies in a New York Amsterdam News column "for being particularly interested in the youngsters of [his] own race."

"We must keep these youngsters aware," Robinson wrote, "that no Negro has it made, regardless of his fame, position or money—until the most underprivileged Negro enjoys his rights as a free man."

In 1949, Robinson made his political presence felt when he was called before the House Un-American Activities Committee to testify against Paul Robeson regarding communism in the black community. Robinson told members of the HUAC that he did not "pretend to be an expert on communism or any other kind of political isms."

Robeson, another multitalented black athlete, who was better known as a singer and actor, was enthralled by communism. Robinson was not. He also was not thrilled to be juxtaposed against another prominent African American, regardless of their differences.

"[He] has a right to his personal views, and if he wants to sound silly when he expresses them in public, that is his business and not mine," Robinson said (via JSTOR), per Paul Robeson and Jackie Robinson: Athletes and Activists at Armageddon by Joseph Dorinson.

Downplaying his own political expertise, Robinson asked HUAC members to see him as "being an expert on being a colored American with 30 years of experience at it," per History.com.

Not all of Robinson's platforms were prototypical of a black athlete. For example, he supported Republican candidate Richard M. Nixon in the 1960 presidential election and Nelson Rockefeller in the 1964 Republican primary. Because of this, conservatives often plunder the political legacy of Robinson, without nods to his complex "militant" politics, such as his stance on political affiliation.

"I'm a black man first," he said in 1968 (h/t The Root), "an American second, and then I will support a political party—third."

Whether Robinson took the popular position or not, he took a position. He stood for something. So as we praise him at every MLB game on April 15, let's keep that same attitude toward today's players in every sport when they don't just shut up and play.

Carl Suddler (Ph.D., history, Indiana University) is an assistant professor of African American history in the Department of History at Florida Atlantic University. He is the author of the forthcoming Presumed Criminal: Youth, Race, and Justice in an American City (NYU Press), which examines racialized constructions of youth criminality in New York City from the 1930s to the 1960s.