Democratic U.S. Senator Cory Booker accused U.S. President Donald Trump of "recklessly" attacking the nation's democratic institutions in a marathon speech that was approaching a record on Tuesday.

The 55-year-old New Jersey lawmaker, in a speech that began at 7 p.m. ET on Monday and went on through the night and into Tuesday afternoon, criticized the campaign by the Republican president and his key adviser Elon Musk, the world's richest person, to slash large swaths of the federal government.

"Our institutions are being recklessly and unconstitutionally attacked and even shattered," said Booker, first elected to the U.S. Senate in 2013.

In his first weeks back in office, Trump's administration has moved to outright shutter certain arms of the government, including the U.S. Department of Education, withheld congressionally approved spending and has questioned the authority of the federal courts to constrain its policies.

Democratic voters have become angry in recent weeks as Trump, backed by a Republican-controlled Congress, has shaken up long-established U.S. alliances and cut more than 100,000 federal workers. This anger has been aimed both at Republican lawmakers and the Democratic party's own leaders, including top Senate Democrat Chuck Schumer, for co-operating with Senate Republicans to pass a government funding bill that averted a partial shutdown.

"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 approaching Senate record

By Tuesday afternoon, Booker was approaching the all-time Senate record for longest continuous speech, which is currently held by the 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.

Since Booker's speech is not aimed at a specific piece of legislation, it's 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.

By Tuesday afternoon, he began to show signs of strain. When he dropped a piece of paper from his desk he looked down, very slowly and carefully began bending to pick it up only to be rescued by fellow Democratic Senator Michael Bennet of Colorado, who sprang to his aid.

A unifying theme of Booker's wrath was Musk's campaign to slash the size and scope of the U.S. government.