Joy, vindication and anxiety: Democrats absorb a consequential moment.

In some ways, it was the turn of events Democratic voters had dreamed of and some of the party’s lawmakers had long demanded: After years of telling lies, shattering norms, inciting a riot at the Capitol and being impeached twice, Donald J. Trump on Thursday became the first former president to face criminal charges.

“We’ve been waiting for the dam to break for six years,” declared Carter Hudgins, 73, a retired professor from Charleston, S.C. “It should have happened a long time ago,” added his wife, Donna Hudgins, 71, a retired librarian.

But as the gravity of the moment sank in, Democratic voters, party officials and activists across the country absorbed the news of Mr. Trump’s extraordinary indictment with a more complex set of reactions. Their feelings ranged from jubilation and vindication to anxieties about the substance of the case, concerns that it could heighten Mr. Trump’s standing in his party and fears that in such a polarized environment, Republicans would struggle to muster basic respect for the rule of law as the facts unfolded.

“They are going to treat him as if he is Jesus Christ himself on a cross being persecuted,” said Representative Jasmine Crockett, a Texas Democrat from Dallas who worked as a criminal defense lawyer before she was elected to Congress last year. She blasted Republican arguments that the charges were politically motivated, saying, “We knew the type of person Trump was when he got elected the first time.”

Mr. Trump, who polls show is the leading Republican contender for the 2024 presidential nomination, was indicted on Thursday by a special grand jury in connection with his role in hush-money payments to a porn star. He was charged with more than two dozen counts, though the specifics are not yet known.

It is one in a swirl of investigations Mr. Trump faces, on a range of explosive matters including his handling of sensitive government documents after leaving office and whether he and his allies criminally interfered with the 2020 presidential election. He could face multiple other indictments.

But the one this week, centered on a tawdry episode that predates Mr. Trump’s time in the White House, struck some Democrats as a sharp contrast in substance with the other possible charges against the former president. Some felt conflicted between their view that no one is above the law, while wondering if this particular case will be worth the chaos for the country, especially when there may be other, bigger targets.

“He isn’t above the law and anyone who suggests otherwise is un-American,” said Matt Bennett, a co-founder of Third Way, a centrist Democratic organization. “The question is, is it worth it for this crime?”

In Littleton, N.H., Bernd Weber, 65, a dentist, said he was glad the grand jury had voted to indict Mr. Trump, but he worried about the former president’s ability to “spin it to make it look like a witch hunt, and there are people that are buying that.”

“There were any number of things that he could have been indicted for, and this was probably the least of them,” he said.

Other Democrats made clear that while they welcomed this indictment, they believed Mr. Trump should be held accountable for far more.

“No one is above the law,” Representative Barbara Lee, a liberal California lawmaker now running for Senate, wrote on Twitter. “Now do the rest of his crimes.”

Jon Hurdle contributed reporting from Littleton, N.H., and Melissa Delaney from Charleston, S.C.