Former President Barack Obama on Friday criticized the claims of an anonymous New York Times op-ed, which said many staffers are “working diligently from within” to keep President Donald Trump from enacting damaging policies.

“That is not a check, I’m being serious here. That’s not how our democracy’s supposed to work,” Obama said while speaking at the University of Illinois Urbana–Champaign. “These people aren’t elected. They aren’t accountable. They’re not doing us a service by actively promoting 90 percent of the crazy stuff that’s coming out of this White House and then saying, ‘Don’t worry, we’re preventing the other 10 percent.’ That’s not how things are supposed to work. This is not normal.”

The Times says the op-ed, published Wednesday, was written by a senior official in the Trump administration. A slew of officials working in the administration issued statements Thursday in which they denied authoring the piece. CNN reported Trump was closely monitoring the denials, according to a top White House official.

Trump has argued the op-ed is “treason” and a product of the so-called “Deep State.” He has also said the Times should reveal the author “for National Security purposes” and that Attorney General Jeff Sessions should investigate.

During his remarks, Obama also criticized Republicans in Congress who seem “utterly unwilling” to stand up to Trump and “safeguard the institutions that make our democracies work.”

“These are extraordinary times,” he said. “These are dangerous times.”

The speech marked Obama’s strongest rebuke of Trump since he left office in January 2017. Obama was in Illinois to accept an award for ethics in government from the University of Illinois.

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This article originally appeared on HuffPost.