Hillary Clinton launched stinging criticism of Donald Trump on Friday, even suggesting her likely Republican presidential opponent wants to be America's "dictator," as she proclaimed she will be the Democratic flag bearer once California votes next week. President Barack Obama lent his voice to the denunciation, saying Trump's aggressive posture towards immigrants, Muslims and women is "feeding resentments" among Americans and urging them to seek out scapegoats for their frustrations and problems. Amid increasingly brazen attacks on both sides, Clinton and Trump are emerging as the two rivals who will do battle in the general election. Trump is already the presumptive Republican nominee, while Clinton has begun talking as if she is the Democratic flag bearer. "We need everybody to show up on June 7," she told a few hundred supporters at a college in Culver City, California. "If all goes well, I will have the great honor as of Tuesday to be the Democratic nominee for president," she said to loud cheers. Democrats in six states vote Tuesday, including California and New Jersey. Clinton is already on the cusp of securing enough delegates to defeat Sen. Bernie Sanders for the nomination and she is certain to surpass the threshold on June 7. Sanders has been barnstorming California, hoping for a miracle in which he wins the remaining contests and many so-called super-delegates, senior party figures who can vote at the party convention for whomever they choose, switch alliances and support him. But Clinton barely mentioned Sanders's name, opting instead for a full-on assault on Trump during her four stops Friday, in Culver City, Westminster, Santa Ana and San Bernardino. "Donald Trump is not qualified to be president and commander in chief," she said. Clinton added that she was appalled at the tenor of the political discourse, suggesting Trump was straying from democratic principles. "We are trying to elect a president, not a dictator," she said in San Bernardino. She battered Trump over his character and his lack of coherent foreign policies, branding him "temperamentally unfit" and otherwise unprepared to lead the United States. "He just engages in rants and personal feuds and outright lies, something our nation cannot afford in our commander in chief," the former secretary of state said. More than a dozen women — Hollywood actresses, members of Congress, and civil servants — joined her on stage in Culver City to offer their support. "She is bad-ass, and she is ready to lead," US House Democrat Linda Sanchez boomed. While Clinton has upped her attacks on Trump as a fraud, Trump has drilled into Clinton as dishonest and "crooked." But Trump, who has faced repeated accusations of racism and xenophobia, waded deeper into controversy Friday after praising a black supporter as "my African American" at a rally in Redding, California. "Oh, look at my African American over here. Look at him," Trump said. "Are you the greatest?" Campaign spokeswoman Hope Hicks said there was "no ill will intended, obviously." Trump also hit out at the protesters — he labeled them "thugs" — who clashed with his supporters in California the previous evening, the latest in a string of his rallies to be marred by violence. Hundreds of demonstrators insulted Trump supporters as they tried to leave the event in San Jose. People hurled eggs, and according to the Los Angeles Times a dozen or more people were punched. Crowds had earlier chanted "No hate in our state" and carried signs that read "Dump Trump" as they marched near the convention center. Hispanics outnumber whites in California, the most populous US state, and many have been shocked by Trump's characterization of Mexican immigrants as "rapists" and his pledge to build a wall along the southern US border. Trump stepped up attacks Friday against the judge handling a class action lawsuit of former students against the now defunct Trump University. The students claim the program was a scam. Clinton sounded incredulous that Trump would insult and attack the judge. "What more represents the American dream than this family?" she asked. Trump's attack on the judge earned swift condemnation from House Speaker Paul Ryan, the nation's top elected Republican, who only a day earlier said he would vote for the billionaire in November after weeks of hesitation. "I completely disagree with the thinking behind that," Ryan said in a radio interview.