California Rep. Adam Schiff said "it's a sober moment for the country," telling Linsey Davis on ABC News Live on Thursday that the dignity of the Oval Office "will be tarnished by the conduct of the former president by his being charged criminally."

"I think you have to be guided by the facts and the law, and you have to set aside the political calendar and do what the law requires," said Schiff, a leading Democrat in the House. "I think that's the obligation of a district attorney, and I think that was done here. How this cuts politically, I really don't know. That, to me, is very secondary."

-ABC News' Imtiyaz Delawala and Anna Katharine Ping

Demonstrators gathered outside Manhattan Criminal Court and near Donald Trump's Mar-a-Lago estate in Florida in the wake of the indictment Thursday evening.

In Manhattan, a giant sign that stated "Trump lies all the time" could be seen unfurled outside Manhattan Criminal Court, where police had erected barricades last week ahead of a possible indictment.

Meanwhile, several supporters gathered near Mar-a-Lago with Trump 2024 flags and signs.

Senate Majority Leader Chuck Schumer urged "Trump’s critics and supporters to let the process proceed peacefully and according to the law" in a statement following the indictment of the former president.

"Mr. Trump is subject to the same laws as every American," Schumer said. "He will be able to avail himself of the legal system and a jury, not politics, to determine his fate according to the facts and the law."

Lawmakers on both sides of the aisle took to Twitter to react to the historic indictment on Thursday evening, laying bare the sharp partisan divide when it comes to Donald Trump.

GOP House and Senate members decried the investigation by the Manhattan district attorney as a political prosecution.

Many Democrats, on the other hand, praised the decision as proof "no one is above the law."

Read more here.

-ABC News' Alexandra Hutzler

Donald Trump's former personal attorney and fixer Michael Cohen said the ex-president is likely "seething" over the indictment because he's "never been held accountable."

"The fact that he is being held accountable, something that he has no desire to ever be. He's never been held accountable," Cohen told ABC News' George Stephanopoulos in an interview Friday on "Good Morning America."

"This is a man who held up the Bible and said he's never apologized to God because he's never done anything wrong," he added. "He doesn't understand accountability. And right now, [Manhattan District Attorney] Alvin Bragg has finally put that into his lap."

Cohen, who is now estranged from Trump and is a key prosecution witness, said he decided years ago that his "loyalty can no longer be to a man who doesn't deserve it."

Cohen was sentenced to three years in prison in December 2018, after pleading guilty to violating federal campaign finance law in connection with hush-money payments and lying to Congress, among other crimes.

During Friday's interview on "GMA," Cohen said he followed Trump's "message" for more than a decade and "that is what got me in trouble."

When asked if he feels ready to be cross-examined, Cohen replied: "Absolutely."

"The documents will speak for themselves," he added, referring to the sealed indictment.

"So, not just your testimony?" Stephanopoulos responded.

"No," Cohen said. "And it's also corroborating testimony, but it's documents."