WASHINGTON >> President Donald Trump has decided on his Supreme Court nominee, a person with knowledge of the situation revealed today, hours before a prime-time TV announcement that will ignite a fierce confirmation battle.

As others speculated about his nomination to replace retiring Justice Anthony Kennedy, Trump had little to say about his choice, who could cement a conservative majority on the court for years to come. But he did make his pick, according to a person who was not authorized to speak publicly and commented only on condition of anonymity.

After a weekend deliberating with aides and calling allies for advice, he tweeted, “I have long heard that the most important decision a U.S. President can make is the selection of a Supreme Court Justice – Will be announced tonight at 9:00 P.M.”

I have long heard that the most important decision a U.S. President can make is the selection of a Supreme Court Justice – Will be announced tonight at 9:00 P.M.

— Donald J. Trump (@realDonaldTrump) July 9, 2018

Top contenders for the role have included federal appeals judges Brett Kavanaugh, Raymond Kethledge, Amy Coney Barrett and Thomas Hardiman. The White House has been preparing information materials on all four, who were part of a longer list of 25 names vetted by conservative groups.

While the president has been pondering his pick, aides have been preparing for a tough confirmation fight. The White House said today that former Sen. Jon Kyl of Arizona would guide the nominee through the Senate confirmation process.

Before retiring in 2013, Kyl was a member of the Senate Judiciary Committee, which will be the first to consider the nomination. He now works for the Washington-based lobbying firm Covington & Burling. The White House hopes Kyl’s close ties to Senate Republicans will help smooth the path to confirmation.

The White House guest list for the Monday night announcement includes Judiciary Committee chairman Chuck Grassley, R-Iowa, and another committee member, John Kennedy, R-La.

Kennedy said he was bracing for a tough confirmation battle as Democrats focus on the nominee’s views of the high court’s Roe v. Wade ruling legalizing abortion.

“I suspect this is going to be a rough, tough, down in the dirt, ear-pulling, nose-biting fight,” Kennedy said.

Trump is hoping to replicate his successful nomination of Justice Neil Gorsuch last year.

The president has spent the days leading up to his announcement discussing the pros and cons of the various options with aides and allies. He expressed renewed interest in Hardiman — the runner-up when Trump nominated Gorsuch, said two people with knowledge of his thinking who were not authorized to speak publicly. But the situation appeared to remain fluid.

Hardiman has a personal connection to the president, having served with Trump’s sister on the 3rd U.S. Circuit Court of Appeals in Philadelphia. He also has a compelling personal story: He went to the University of Notre Dame as the first person in his family to go to college. He helped finance his law degree at the Georgetown University Law Center by driving a taxi.

Some conservatives have expressed concerns about Kavanaugh — a longtime judge and former clerk for Justice Kennedy — questioning his commitment to social issues like abortion and noting his time serving under President George W. Bush as evidence he is a more establishment choice. But his supporters cite his experience and wide range of legal opinions. He is also former law clerk to Kennedy, as is Kethledge.

Barrett — a longtime Notre Dame Law School professor who became a federal appeals judge last fall — excited social conservatives with her testimony when she was questioned about her Roman Catholic faith in her nomination hearings last year. But her brief time on the bench has raised questions about her experience

Kethledge serves as a judge on the U.S. Court of Appeals for the 6th Circuit in Cincinnati. He co-authored a book with Army veteran Mike Erwin of The Positivity Project published last year called “Lead Yourself First: Inspiring Leadership Through Solitude.”

Trump has enjoyed teasing details of his process in recent days, saying Thursday that he was down to four people and “of the four people, I have it down to three or two.” On Saturday, he tweeted that a “Big decision” was coming soon. On Sunday he was back to citing “the four people.”

The president and White House officials involved in the process have fielded calls and messages and have been on the receiving end of public pleas and op-eds for or against specific candidates since Kennedy announced on June 27 that he would retire this summer.

Republican Sens. Lindsey Graham of South Carolina and Roy Blunt of Missouri said Sunday that they believe any of the top four contenders could get confirmed by the GOP-majority Senate.

“They’re good judges,” Blunt said on NBC’s “Meet the Press.” He added: “I think they’d be fine justices of the Supreme Court. I do think the president has to think about who is the easiest to get confirmed here. And I expect we will do that on sort of a normal timetable, a couple of months.”

Outside adviser Leonard Leo, currently on leave from the Federalist Society, said on ABC’s “This Week” on Sunday that this kind of jockeying is standard, noting that “every potential nominee before announcement gets concerns expressed about them by people who might ultimately support them.”