WATCH LIVE: President Trump Announces Pick For Supreme Court Judge

Updated at 5:25 p.m. ET

With just hours to go before the official announcement, President Trump has made a decision on his pick for the next Supreme Court justice, a source close to the decision-making process tells NPR's Mara Liasson.

But there is still no indication which of the four finalists it will be.

As of Monday morning, Trump was still deciding among Judges Thomas Hardiman, Brett Kavanaugh, Raymond Kethledge and Amy Coney Barrett.

The last thing Washington needs right now is another blockbuster news story.

But here it comes anyway, President Trump's latest choice to serve on the U.S. Supreme Court. At a minimum, that person will be the center of attention in Washington through much of the summer and fall, through Senate hearings and deliberations — after which the nominee is highly likely to be confirmed and to serve on the nation's highest court for decades.

When it comes to Washington news stories, it doesn't get much bigger than that.

Updated at 4:45 p.m. ET

The final hours of President Trump's decision-making on his second Supreme Court nominee are being described as hectic and unpredictable — and the president has still not made a decision.

"It's insane" over there, said a source close to the process. Few have had any sleep in Bedminster, N.J., as deliberations continue over the pros and cons of the potential nominees, and no one is sure which way the president is going to go, the source said.