WARSAW — A 25-year-old psychologist, Anna Suchodolska joined the recent protests against the government’s moves to place Poland’s courts under its thumb. She was relieved when the president unexpectedly vetoed the laws this week.

But she is under no illusion that the crisis is over, or that the governing party won’t just find another way to do what it wants. If the protests resume, she will be there again, she said.

“My dad said to me that I need to act now so I don’t cry later,” Ms. Suchodolska said, smoking a cigarette in the crowded plaza outside Warsaw’s largest shopping mall. “He said he’s too old, but I am young and I have to fight for my rights and my children’s.”

For 21 months since it was elected, Poland’s government under the conservative, nationalist Law and Justice party has wobbled one pillar of the country’s democratic institutions after another. Only on occasion did Poles take to the streets.