Biden to blast 'dangerous' Trump in 2024 democracy speech

President Joe Biden will warn that Donald Trump and his "extremist" allies pose a danger to U.S. democracy in a speech Thursday, sharpening his attacks on his likely Republican challenger in the 2024 election.

The Democrat will say in the battleground state of Arizona that there is a "threat to our institutions, to our constitution itself" from the right-wing populist, who is neck-and-neck with Biden in the polls, despite facing dozens of criminal charges.

To avoid appearance of judicial interference, Biden has steered clear of commenting on the indictments against Trump, including over his involvement in efforts to overturn his 2020 election loss -- culminating in mayhem unleashed by his supporters at the U.S. Capitol on January 6, 2021.

But Biden, 80, is not holding back in dark warnings about what he says the country would risk from a second Trump term.

"There is something dangerous happening in America," Biden will say, according to excerpts released by the White House of his speech in Tempe, Arizona.

"There is an extremist movement that does not share the basic beliefs of our democracy. The MAGA Movement," he will say, referring to Trump's slogan, Make America Great Again.

The speech comes as House Republicans on Thursday launch impeachment inquiry hearings into Biden, based on unproven allegations that he lied about his son Hunter's business dealings.

It also comes as the United States heads for a government shutdown this week, with Congress in deadlock over hardline Republican calls for deep spending cuts.

Trump this week pushed for Republicans to "shut it down" unless they got all the concessions they wanted, saying that Biden would be blamed for the dysfunctional situation.

'UNITE ALL AMERICANS'

Biden, however, will tout his bipartisan credentials by using the speech to hail the legacy of his frequent political opponent and close friend -- the late Arizona senator John McCain.

McCain, a Vietnam war hero, was defeated in the 2008 presidential election by Barack Obama -- with Biden on the winning ticket as vice president. But the two men put aside differences particularly after Trump won his own presidential election in 2016.

Biden will describe McCain, who died in 2018, as a "proud Republican who put country first."

"Our commitment should be no less because democracy should unite all Americans -- regardless of political affiliation," he will add.

McCain loathed Trump, withdrawing his support for him in the 2016 presidential election and saying before his death from brain cancer that he didn't want him at his funeral.

The feeling was mutual, with Trump mocking his war hero status in 2015.

Biden, on the other hand, delivered a eulogy at McCain's funeral, saying that he "loved" him and that their friendship transcended political differences.

Biden has given a series of speeches on the defense of democracy, often retelling the story about how he retirement to run for president after he heard Trump refusing to clearly denounce a neo-Nazi rally in Charlottesville in 2017.

While the U.S. election is still more than a year away, Biden and Trump notched up their first major head-to-head skirmish this week with dueling visits to auto industry workers in Michigan, another battleground state.

Biden joined a picket line of striking union workers on Tuesday and Trump addressed and Trump addressed employees at a non-unionized facility on Wednesday.

Biden's speech comes the day after seven other Republican presidential hopefuls held a campaign debate in California. Trump, who holds overwhelming leads over all of his rivals, snubbed the event.