BUDAPEST — Gyula Radics is not easily angered. When Prime Minister Viktor Orban rewrote the Constitution to give his party greater power, he stayed on the sidelines. When the party took over state media, he was silent. And when the government forced the internationally renowned Central European University out of Hungary, he did not join the protests.

But after Mr. Orban pushed through legislation compelling employees to work hundreds of hours of overtime without full or immediate compensation, he had enough.

“Orban destroys lives and families,” Mr. Radics said as he prepared to march with thousands of protesters Saturday afternoon. A 39-year-old steelworker with five children, he traveled from Veszprem, an hour outside of Budapest.

“This is all we have left,” he said.

By this, he meant the streets.

Over the past eight years, Mr. Orban has steadily used the instruments of a democratic state to undermine nearly all checks on his power.