US former president Donald Trump pleaded not guilty on Thursday to criminal charges that he conspired to overturn the results of the 2020 election and defraud the American people.

Trump, the frontrunner for the 2024 Republican presidential nomination, entered his plea during a nearly 30-minute hearing at the same Washington courthouse where hundreds of his supporters have been convicted for their roles in the January 6, 2021 attack on the US Capitol.

“Not guilty,” Trump said after magistrate judge Moxila Upadhyaya read the four criminal counts — and the potential maximum prison sentences — in the 45-page indictment brought by special counsel Jack Smith.

The 77-year-old has already been charged in two other criminal cases, and the new conspiracy charges raise the prospect of his being further embroiled in legal proceedings at the height of next year’s election campaign.

Speaking to reporters at Reagan National airport before leaving Washington on his private plane, Trump said the cases brought against him were “persecution of a political opponent.”

“This is a very sad day for America,” he said. “This is the persecution of the person that’s leading by very, very substantial numbers in the Republican primary and leading (President Joe) Biden by a lot.

“So if you can’t beat him, you persecute him or you prosecute him,” he said. “We can’t let this happen in America.”

Later on Thursday, Trump quipped on his Truth Social account that considering he had to journey “to a filthy, dirty, falling apart & very unsafe Washington” for his arraignment, “it was a very good day!”

The judge set the next hearing in the high-stakes case for August 28 before US District Court Judge Tanya Chutkan, who will preside over the eventual trial.

“I can guarantee to everybody there will be a fair process and a fair trial,” Upadhyaya said.

– ‘Fueled by lies’ –

Security was tight around the E. Barrett Prettyman federal courthouse where the hearing was held, with metal barricades blocking access and police patrolling the perimeter.

Small groups of demonstrators holding placards milled about outside along with curious tourists.

“Jail Trump Forever,” read one sign. “Trump 24,” read another.

“We wanted to see it,” said Dave Werner, 52, of Houston, Texas, who was visiting the capital with his son Liam, 12. “It’s a little bit being part of history.”