Hillary Clinton returned to her alma mater Friday and delivered a remarkable rebuke, not just to the right-wing policies but to the disdain for truth that is so frequently evidenced by the man she beat by almost 3 million votes in the 2016 presidential election.

President Trump’s budget, Clinton told Wellesley College graduates in a compelling commencement address, represents

An attack of unimaginable cruelty on the most vulnerable among us—the youngest, the oldest, the poorest, and hard working people who need a little help to gain or hang on to a decent, middle-class life. It grossly underfunds public education, mental health, and efforts even to combat the opioid epidemic. And in reversing our commitment to fight climate change, it puts the future of our nation and our world at risk.

Ripping a White House plan that is “shrouded in a trillion-dollar mathematical lie,” she declared, “Let’s call it what it is: a con. They don’t even try to hide it.”

Clinton grounded her denunciation of the Trump agenda in an impassioned defense of American values. Her remarks combined humor, insight, and ardent advocacy for a radically different vision of the the country’s future. Her speech embraced the resistance to the Trump administration and its toxic brew of “alternative facts,” jabs at journalists and dismissals of critical inquiry.

“There is a full-fledged assault on truth and reason,” Clinton explained. “Just log on to social media for ten seconds, it will hit you right in the face. People denying science, concocting elaborate hurtful conspiracy theories about child abuse rings operating out of pizza parlors, drumming up rampant fear about undocumented immigrants, Muslims, minorities, the poor…. Some are even denying things we see with our own eyes, like the size of crowds. And then defending themselves by talking about quote-unquote alternative facts.”

At the core of her message was a defense of open and honest debate based in reality rather than White House spin. In the most powerful portion of her speech, Clinton warned that the discourse and, yes, democracy itself, are threatened by an administration that refuses to acknowledge the truth.

“When people in power invent their own facts and attack those who question them, it can mark the beginning of the end of a free society,” Clinton declared. “That is not hyperbole. It is what authoritarian regimes throughout history have done. They attempt to control reality—not just our laws and our rights and our budgets, but our thoughts and beliefs.”

One does not need to be a Clinton enthusiast to recognize the importance of the speech she delivered at Wellesley. There’s plenty to criticize about her 2016 presidential run—Clinton freely acknowledges that she did not run a perfect campaign—but this was a commencement address, not a campaign speech. It contained within it a necessary argument against complacency at a time when the basic premises of the American experiment are under attack.

Clinton used the bully pulpit that is afforded defeated presidential candidates—especially those who prevailed in the popular vote even as they fell short in the Electoral College—to argue against the normalization of Trumpism.

“If our leaders lie about the problems we face, we’ll never solve them. It undermines confidence in government as a whole,” Clinton explained. “It also matters because our country was founded on the principles of the enlightenment, in particular the belief that people possess the capacity for reason, and that free and open debate is the lifeblood of a democracy.”

Of course, Clinton’s critics will object to her tone. They always do. In particular, Trump enthusiasts will be unsettled by her comparison of the moment in which the Wellesley College Class of 2017 is graduating with the moment in which her own Wellesley College Class of 1969 graduated.

“We were furious about the past presidential election of a man whose presidency would eventually end in disgrace with his impeachment for obstruction of justice, after firing the person running the investigation into him at the Department of Justice,” she recalled, with a reference to Richard Nixon that drew roars of approval from a crowd who immediately recognized a historical synchronicity at the close of a month that began with Trump’s firing of FBI director James Comey.

While Clinton’s partisan critics will gripe about her tone, their real objection will be to her truth.

There is nothing Democratic or Republican, nothing left or right, in a defense of the principles of the enlightenment, of a faith in reason and facts. It is American to say, as Hillary Clinton did on Friday, that we must all “Stand up for truth and reason. Do it in private—in conversations with your family, your friends, your workplace, your neighborhoods—and do it in public—in Medium posts, on social media, or grab a sign and head to a protest. Make defending truth and a free society a core value of your life every single day.”