U.S. Sen. Cory Booker has kicked off what he promises to be a marathon speech on the Senate floor.

Starting at 7 p.m. ET on Monday, Booker began criticizing President Donald Trump and Elon Musk.

“I’m heading to the Senate floor because Donald Trump and Elon Musk have shown a complete disregard for the rule of law, the Constitution, and the needs of the American people,” Booker posted on X earlier in the day.

“I am not going to stop speaking, I am not going to stop standing,” he said. “I am going to go for as long as I’m physically able to go.”

Once he took the Senate floor, Booker said the president has “inflicted so much harm on Americans’ safety, financial stability, the core foundations of our democracy.”

“I rise tonight because I believe sincerely that our country is in crisis,” he said.

Meanwhile on Sunday, Trump said he was serious about pursuing a third term in office, even though the nation’s highest office is limited to two terms by the U.S. Constitution.

Talking to NBC News Sunday, Trump pointed to his poll numbers as evidence that “a lot of people would like me to” hold office for another term. Trump’s approval ratings for his first few weeks in office are some of the worst in modern history, beating only his own in 2017.

Here’s what we know about Booker’s marathon speech, how long it could go and why it isn’t technically a filibuster.

Who is Cory Booker?

Cory Booker is U.S. Senator who has represented New Jersey since 2013, when he became the first Black person to hold the seat.

The D.C. native and Democrat who was raised in New Jersey completed his undergraduate and master’s degree at Stanford University and graduated from Yale Law School in 1997. He previously served as the mayor of Newark between 2006 and 2013.

Is Cory Booker’s speech a filibuster?

Cory Booker’s speech is not considered a filibuster as he is not attempting to delaying a legislation or a nomination from passing.

How long can Cory Booker hold the Senate floor?

Though lawmakers finished voting on Monday, the Senate floor will remain open for as long as his remarks last.

How to watch Cory Booker’s marathon speech?

Senator Booker’s speech can be watched on C-SPAN, as well as social media platforms X, Facebook and YouTube.

How common are marathon Senate speeches?

Lengthy speeches and controlling the floor have long been a means of protest in the upper chamber. 

In 2017, Democratic Oregon Sen. Jeff Merkey spoke for 15 hours, 26 minutes against the nomination of Neil Gorsuch to the Supreme Court. In 2013, Republican Texas Sen. Ted Cruz spoke for 21 hours and 19 minutes against the Affordable Care Act, according to the Senate Information office.

Former South Carolina Sen. Strom Thurman filibustered for over 24 hours in an attempt to prevent the passage of the Civil Rights Act in 1957. The speech is the longest in the Senate record, breaking the previous record of former Sen. Wayne Morse at over 22 hours.

Contributing: James Powel, Kinsey Crowley