Democratic US Senator Cory Booker has accused President Donald Trump of "recklessly" challenging the nation's democratic institutions in a marathon speech that broke a nearly seven-decade record for length.
The 55-year-old New Jersey lawmaker, in a speech that began at 7 pm on Monday and went on for more than 24 hours, criticised the crusade by the Republican president and his billionaire top adviser Elon Musk to slash large swaths of the federal government.
"Our institutions are being recklessly and unconstitutionally attacked and even shattered," said Booker, who was first elected to the Senate in 2013.
Booker, who is Black, broke the record for the longest continuous speech previously held by segregationist Senator Strom Thurmond of South Carolina.
In the summer of 1957, Thurmond launched a filibuster against civil rights legislation that lasted 24 hours and 18 minutes. In the end, Thurmond failed in his mission to block a bill that expanded federal protections of voting rights for Black people.
Booker, whose speech was not a filibuster - a tactic to delay or kill action on specific legislation - passed Thurmond's record and continued to speak.
He repeatedly referred to activists getting into "good trouble" by speaking out against Trump's actions, using a term that the late Democratic Representative John Lewis, a civil rights leader, had often employed.
Trump, in his first weeks in office, has moved to outright shutter government arms, including the Department of Education, and withhold congressionally approved spending. His administration has also questioned the authority of the federal courts to constrain its policies.
Booker acknowledged the Democratic voter anger about 24 hours into his speech, saying, "I was challenged by my own constituents to do something different, challenged by my own constituents to do something, challenged by my own constituents to take risks."
A White House spokesman dismissed Booker's criticism.
"Cory Booker is looking for another 'I am Spartacus' moment, but that didn't work for his failed presidential campaign, and it didn't work to block President Trump's Supreme Court nominee, Brett Kavanaugh," said Deputy White House press secretary Harrison Fields.
Booker had made a run for the Democratic presidential nomination in 2020, the year that Trump ultimately lost his bid for re-election to Joe Biden.
Musk, the world's richest person, has been heading up the Trump administration's Department of Government Efficiency, which is intent on slashing federal spending.
Booker's speech, since it is not aimed at a specific piece of legislation, is not technically considered a filibuster, though it has halted other Senate action.
The only breaks Booker took were when a stream of fellow Democrats, one by one, came to the floor to ask him a question, allowing him to keep control of his speaking time.
Musk's targets - and thus Trump's - include eliminating many US foreign aid programs and cutting workers at federal departments that provide public health services, healthcare to veterans and the Social Security Administration, which oversees federal retirement programs.
"The Trump-Vance administration continues to plunge us into chaos," Booker said.
"Trump's trade war on our allies will only increase costs and fears for American families."
With AAP.