Donald Trump, the former U.S. President, found himself in the eye of a legal storm on Tuesday at a courthouse in Miami, facing criminal charges linked to his alleged illegal retention of classified national security documents post-presidency and his subsequent dishonesty to officials endeavoring to recover them.

Trump, along with his former aide Walt Nauta, were both taken into custody pending their arraignment, according to a court representative. Their plea submission was scheduled for the afternoon, in a session set to exclude live broadcasting and cameras.

This instance marks Trump's second courtroom appearance in recent times, having previously denied guilt over state charges related to hush-money payments in a New York case in April. Tuesday's proceedings, however, pertained to federal charges.

As Trump's motorcade arrived at the courthouse, supporters clad in 'Make America Great Again' hats and brandishing American flags voiced their allegiance with chants of "Miami for Trump" and "Latinos for Trump." The chant "USA! USA!" echoed amongst the crowd. Miami's Mayor, Francis Suarez, assured the media that security had been maintained despite the large gathering.

Officials had prepared for crowd numbers reaching up to 50,000, given the precedent set by the violent attack on the U.S. Capitol on January 6, 2021.

Trump has adamantly maintained his innocence, condemning the proceedings as a witch-hunt orchestrated by President Joe Biden's administration. On social media, he labeled Special Counsel Jack Smith, the prosecution lead, as a "Trump hater."

The grand jury indictment disclosed last week accuses Trump of endangering national security by taking thousands of classified documents with him upon vacating the White House in January 2021. These sensitive documents were allegedly kept haphazardly at his Mar-a-Lago estate in Florida and his New Jersey golf club.

Images in the indictment display document-filled boxes strewn about in various locations including a ballroom stage, a restroom, and across a storage room floor. Trump is also accused of lying to officials who attempted to retrieve the documents, marking the first indictment of a former U.S. President on federal charges in American history.

The charges also suggest Trump conspired with Nauta to withhold classified documents from a federal grand jury.

Despite the legal troubles, Trump's popularity among Republican voters remains undeterred, with an Ipsos/Reuters poll indicating that a substantial 81% view the charges as politically motivated. Several of Trump's Republican competitors have aligned with him, with some going as far as promising a pardon should they secure the presidency.

The unprecedented 37-count indictment encompasses Espionage Act violations, with charges such as unauthorized possession of defense information and conspiracy to obstruct justice, which holds a maximum 20-year sentence.

The complex nature of dealing with classified evidence could delay the trial by a year or more. Despite this, Trump remains free to campaign for the presidency, potentially capable of assuming office even if found guilty.