Bill Nye, former host of educational series “Bill Nye the Science Guy,” took the stage at Washington, D.C.’s “No Kings” rally Saturday to warn those peacefully protesting President Donald Trump that “we are confronting the possible end to our republic.”

“How did we get here?” Nye asked the crowd.

“It hasn’t been one instance of abuse of the power of executive order by this president. It hasn’t been just one twist in a court ruling. Instead, it has been years in the making, enabled by this president. A group of confederates has worked together to undo many of our traditions and understandings of fairness and of citizens’ rights.”

The nationwide anti-Trump rallies have drawn outrage from Republicans, with conservatives painting the demonstrations as “hate-America” rallies and linking them to antifa and Hamas.

Nye told demonstrators that their presence at the rally sends a message to lawmakers, telling them “they must stop the abuses of this petulant president and his circle of sycophants.”