As I sat in the San Diego sunshine yesterday listening to Bernie Sanders outside of Qualcomm Stadium, I was struck by the stunning contrast between the senator and Donald Trump, particularly on the issue of race.

Sanders emphasized racial justice, citing the courage of African Americans and their allies who fought against racism and bigotry during Jim Crow. He talked of the thousands of undocumented workers who are ruthlessly exploited, overworked and underpaid, vowing to end the current deportation policies. Sanders seeks to “unite, not divide families.” And he wants to “fundamentally change” the federal government’s oppressive relationship with the Native American community.

There are more people in U.S. prisons than in any other country in the world, Sanders noted. Those imprisoned, he said, are disproportionately African Americans, Latinos and Native Americans. The senator wants to invest in “jobs and education, not jails and incarceration.”

Sanders was a leader in the Civil Rights Movement. He served as president of the Congress of Racial Equality at the University of Chicago, organizing pickets and sit-ins, which led to his 1963 arrest for “resisting arrest.”

When Dr. Cornel West, author of the book Race Matters, introduced Sanders, he said the senator stands on the shoulders of Martin Luther King Jr., Edward Said and Cesar Chavez. Said, a professor at Columbia University, was a path-breaking Palestinian-American activist scholar, who decried the “dehumanization of Palestinians to the level of beasts virtually without sentience or motive.”

The overwhelming popularity of Sanders prompted the Democratic National Committee to invite him to nominate several members to the platform committee for the Democratic Convention. Much to the consternation of Hillary Clinton, Sanders’ choices included Dr. West, Congressional Progressive Caucus chair Keith Ellison, and Arab-American Institute president James Zogby, all staunch supporters of Palestinian rights.

Sanders called out Donald Trump for his bigotry, saying, “In the year 2016, the American people will not accept a bigoted president.” He added, “We are not going back. We will not accept a candidate that insults Latinos, Muslims, women, veterans and African Americans.” Sanders reminded us that Trump was a leader of the birther movement, whose aim was to delegitimize Barack Obama as president because he is black.

Trump has a nasty habit of attacking people based on their race. His most recent assault was on Gonzalo Curiel, a well-respected federal judge in San Diego, who is presiding over a lawsuit filed by people claiming they were scammed by Trump University. When Curiel ordered the unsealing of documents in the case, Trump mounted a double-barrel assault on the judge, stating that Curiel had “an absolute conflict” that should disqualify him from the case. Trump’s reasons: “He is a Mexican.” Trump said, “I’m building a wall. It’s an inherent conflict of interest.” Curiel is a U.S. citizen born to Mexican immigrant parents. Trump also maintains that a Muslim judge might treat him unfairly because the latter has advocated the temporary exclusion of most foreign Muslims from entering the United States. But federal courts have roundly rejected the claim that the ethnicity of a judge disqualifies him or her from hearing a case.

Trump has also vowed to deport 11 million undocumented workers from the United States.

The overt racism of the presumptive Republican presidential candidate is causing hand-wringing in GOP circles. Republican strategist Brian Walsh characterized Trump’s comments as “racist, nonsensical” and “the definition of racism.”

Veteran GOP operative Rick Wilson is also alarmed at Trump’s racism, noting that [the Republican Party] “own[s] the racial animus that started out as a bug, became a feature and is now the defining characteristic of his campaign.” Wilson said that Trump’s comments about Curiel and Muslim judges are “overtly racist.”

Trump’s racism is also evident in his pandering to people based on their race. He recently pointed out a black man in the crowd, declaring, “Oh, look at my African American over here – look at him.”

Sanders has cited Trump’s demagoguery, which, the former thinks, is a reaction to fear and anger that many people feel, leading them to embrace scapegoating.

“Don’t go to the dark side,” Sanders implores. He advocates building a strong, progressive movement. “Real change,” he told us yesterday, “has never taken place from the top on down, only from the bottom up.”