Former US President Donald Trump has held the first rally of his 2024 presidential campaign in Waco, Texas, railing against prosecutors investigating him, and employing dark and conspiratorial language to fire up his base ahead of next year’s Republican primary elections.

Trump — facing potential indictment — opened Saturday’s rally by playing a song, “Justice for All,” that features a choir of men imprisoned for their role in the January 6, 2021, insurrection at the United States Capitol singing the national anthem and a recording of Trump reciting the Pledge of Allegiance.

Some footage from the insurrection was shown on screens.

In his speech, Trump defended the insurrectionists, saying they will be “vindicated”, and described the investigations swirling around him as “something straight out of the Stalinist Russia horror show”.

“From the beginning it’s been one witch hunt and phony investigation after another,” he said.

Trump is being investigated by prosecutors in Manhattan for campaign finance violations stemming from his alleged payment of hush money to an adult film actress ahead of the 2016 election. A special counsel appointed by the Department of Justice is also investigating allegations he hoarded top-secret documents and masterminded a plot seeking to overturn the 2020 election.

Trump declared on Saturday that his “enemies are desperate to stop us,” and “our opponents have done everything they can to crush our spirit and to break our will”.

“But they failed,” he said. “They’ve only made us stronger. And 2024 is the final battle, it’s going to be the big one. You put me back in the White House, their reign will be over and America will be a free nation once again.”

Trump held his rally at the airport grounds in Waco as the city marked the 30th anniversary of a raid by federal agents on the Branch Davidians religious sect there that resulted in 86 deaths, including four law enforcement officers. Many right-wing extremists see the raid as a seminal moment of government overreach, and critics saw the rally’s timing as a nod to Trump’s far-right supporters.

Trump’s campaign insisted the location and timing of the event had nothing to do with the Waco siege or its anniversary.

A spokesperson said the site, 27 kilometres (17 miles) from the Branch Davidian compound, was chosen because it was conveniently situated near four of the state’s biggest metropolitan areas — Dallas/Fort Worth, Houston, Austin and San Antonio — and has the infrastructure to handle a sizable crowd.

Trump did not make any overt references to Waco’s history, telling the crowd he told Texas Lieutenant Governor Dan Patrick he wanted to hold his rally in a place with overwhelming support, not “one of those 50-50 areas”.

He said he told Patrick, “Let’s go right into the heart of it.”

“But as far as the eye can see,” he immediately added, “the abuses of power that we’re currently witnessing at all levels of government will go down as among the most shameful, corrupt, depraved chapters in all of American history.”

Audience members were holding red-and-white signs handed out by the campaign that said “WITCH HUNT” and “I stand with Trump.”

‘High wire’ act

Trump does not just face legal peril. His effort to lock in the Republican nomination faces a potential challenge from Florida Governor Ron DeSantis amid signs that his own support is softening, at least in places like New Hampshire, an early primary battleground.

“I’m not a big fan,” Trump said of DeSantis, accusing him of plotting to slash social security.

“Florida has been tremendously successful for many years, long before this guy became governor.”

The former president is seeking to turn the hush money case in New York City to his advantage by raising money off it and using it to rally supporters. On Friday, he issued an apocalyptic warning, saying the country faced potential “death & destruction” if he was charged with a crime.

In a move that seemed designed to preempt a formal announcement, he claimed last Saturday that he would be arrested the following Tuesday. While that did not happen, Trump has repeatedly invoked violence — urging his supporters to protest — and used increasingly racist and dehumanising rhetoric as he has launched ever more personal attacks against Manhattan District Attorney Alvin Bragg.

But few supporters have heeded his calls to take to the streets to protest his possible indictment in the Manhattan case, and Trump’s escalating rhetoric has repelled at least some within his party.

“Trump is walking on a high wire without a net, telegraphing that he has nothing to lose and is willing to risk dangerous outcomes to rally support,” said Ron Bonjean, a Republican strategist in Washington, DC.

Democrats have also warned that Trump’s remarks had the potential to incite violence.

“The twice-impeached former president’s rhetoric is reckless, reprehensible and irresponsible. It’s dangerous, and if he keeps it up he’s going to get someone killed,” House Democratic leader Hakeem Jeffries of New York said.

At the Waco rally, supporters said they were unfazed by the prospect that Trump could be indicted.

“It’s just another political attack on him to keep him from running and winning this race again,” said Eugene Torres, 41, from the Texas coastal city of Corpus Christi.

Alan Kregel, 56, travelled with his wife from Dallas to see Trump in person for the first time. While he voted for Trump in 2016 and 2020, he said he felt the former president’s “methods and vocabulary” often detracted from his policies. But now, two years out of office, he said he is more supportive of Trump than he was before.

“He’s an innocent man, just persecuted,” said Kregel, arguing an indictment would help Trump win in 2024.

Aside from his attacks on law enforcement and DeSantis, Trump’s speech was largely devoted to prosecuting old grievances and making extreme claims about his enemies.

Several times Trump repeated the false claim that his election loss in 2020 was due to a systemic fraud orchestrated by the Democrats.

Trump painted the stakes of the next election in apocalyptic terms, speaking of “demonic forces” trying to demolish the country, which he said was at risk of falling into a “lawless abyss” unless he is voted back into the White House.

He described some US officials and senior politicians — including Senate Republican leader Mitch McConnell — as a bigger threat to the US than China or Russia.

“Either the Deep State destroys America or we destroy the Deep State,” Trump said.