Trump says he'll plead not guilty after federal indictment

Legal experts say that of all the federal charges Donald Trump and his aide Walter Nauta face in the investigation into the alleged mishandling of top secret government documents, obstruction is one of the most serious.

Claire Finkelstein, the founder and faculty director of the Center for Ethics and the Rule of Law (CERL) at the University of Pennsylvania's Annenberg Public Policy Center, said the obstruction charges in the indictment against Trump and his aide carry as much serious weight as the charges related to keeping the top secret documents, with a maximum penalty of 20 years in prison.

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-ABC News' Ivan Pereira

On the eve of his Tuesday arraignment in Miami, former President Donald Trump made rounds across key conservative media audiences and spoke out against the charges.

Trump told talk show host Howie Carr he would plead "not guilty" at his arraignment and not make a statement during his court appearance on Tuesday.

"I just say, ‘not guilty.’ I didn't do anything wrong. I did nothing wrong. Presidential Records Act. It's not even a criminal event. There's no criminality here. It's ridiculous," Trump said.

Trump also slammed his former attorney general, Bill Barr, who over the weekend had criticized Trump for his alleged mishandling of presidential documents.

“Bill Barr is a failure in so many different ways. But he was a coward. And he didn't do his job," the former president said.

-ABC News' Libby Cathey, Soorin Kim and Isabella Murray

Senate Majority Leader Chuck Schumer called on both supporters and critics of former President Donald Trump to "maintain the peace" as Trump heads to federal court on Tuesday.

"This case must be allowed to play out through the legal process without outside political or ideological interference," Schumer said on the Senate floor Monday. "I encourage both supporters and critics of Donald Trump to maintain the peace and let the justice system do its work."

Republican leader Mitch McConnell has not made any public comments on the indictment since it was handed up on Thursday.

-ABC News' Allie Pecorin

Former President Donald Trump has landed in Florida ahead of his Tuesday afternoon appearance in federal court in Miami.

Trump is spending Monday night at his golf club in Doral, Florida.