During a surprise appearance at the Coachella Valley Music and Arts Festival in Indio, California, on Saturday night, Vermont Senator Bernie Sanders delivered a strong warning concerning President Donald Trump.

Sanders’ unannounced speech urged young people to resist the fossil fuel industry, insurance companies, and states seeking to restrict abortion access.

The crowd booed upon hearing the words “President of the United States,” leading Sanders to respond, “I agree.”

“[Trump] believes climate change is a hoax, which is dangerously wrong,” Sanders cautioned. “You and I must confront the fossil fuel industry and demand they cease the destruction of our planet.”

Since January, the Trump Administration has pursued actions that threaten to undo climate change mitigation efforts, including rolling back protections at the Environmental Protection Agency (EPA) and implementing mass staff reductions at agencies such as the National Oceanic and Atmospheric Administration (NOAA).

Bernie Sanders made a surprise appearance at Coachella efore introducing Clairo.

“Our nation faces significant challenges, and America’s future hinges on your generation,” Sanders stated, appealing to the youth in attendance. “You can choose to ignore what’s happening, but doing so is at your own risk. We need you to rise up and champion justice – economic, social, and racial justice.”

Sanders further implored the audience to “stand up and fight for women’s rights” and strive for economic fairness and equality.

“Our current economy favors the billionaire class while neglecting working families,” Sanders asserted. He concluded by emphasizing healthcare, urging the crowd to “confront insurance and drug companies and recognize healthcare as a fundamental human right.”

Despite receiving considerable applause, Sanders was present to introduce singer-songwriter Clairo, whom he commended for her activism.

“I’m here because Clairo has leveraged her platform to advocate for women’s rights and to end the devastating war in Gaza, where countless women and children are being killed,” Sanders explained.

Earlier that day, Sanders joined Representative Alexandria Ocasio-Cortez in Los Angeles for their rally, drawing thousands of supporters and featuring performances by musicians Maggie Rogers, Neil Young, and Joan Baez. Sanders and Ocasio-Cortez are touring the country with the goal of confronting oligarchs and corporate interests and addressing the growing influence of billionaires in U.S. politics.

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