No one, perhaps even Mr. Trump himself, knows for sure who he will choose - when the President made his first nominee in 2017, one of the two finalists hadn't been alerted until hours before the announcement - but political professionals and legal experts believe this justice, if confirmed, will likely change the court fundamentally.
Sen. Chris Coons (D., Del.) flipped-flopped on the need for the Supreme Court to have nine justices now that a Republican president is in office, going back on his comments from 2016 that the Senate must confirm President Barrack Obama's nominee.
"I will oppose the nomination the President will make tonight because it represents a corrupt bargain with the far Right, big corporations, and Washington special interests", Casey said in a statement.
Kavanaugh, 53, began his career as a clerk to Kennedy. Jon Tester of Montana face the hard decision of whether to back Mr. Trump's nominee - which could help them win re-election, but at the cost of aggravating the Democratic Party's aggressive left wing.
Federal judge Brett Kavanaugh is often mentioned as being the one candidate who checks all the boxes important to Trump.
Leo said: "Brett Kavanaugh and Amy Barrett have a lot of name recognition among supporters of the president, and I think that ultimately when people like them are nominated, you'll see a lot of folks line up". "They're good judges. I think they'd be fine justices of the Supreme Court".
When he was running for United States president, Donald Trump released a list of 11 candidates he would consider for a position on the Supreme Court.
Liberal groups have geared up to protect Roe v. Wade, the Supreme Court case that upheld women's rights to an abortion, from being overturned.
Besides records from his 12 years as an appellate judge, Kavanaugh was a top adviser to President George W. Bush and worked for Kenneth Starr on the years-long Whitewater investigation into Bill and Hillary Clinton.
During Trump's presidential campaign, he emphasized that he would appoint conservative justices to the Supreme Court bench if he was elected.
Decisions on these and otherhot topics of the Trump years - the North American free-trade agreement and climate change - are reversible by a future presidential administration, perhaps by a moderate Republican White House or, nearly certainly, a Democratic administration.
Republican Sens. Lindsey Graham of SC and Roy Blunt of Missouri said Sunday that they believe any of the top four contenders could get confirmed by the GOP-majority Senate.
"The president has to think about who is the easiest to get confirmed here", Blunt said.
Barrett, who is 46, has less of a judicial record to review, having just been nominated to the appeals court by Trump past year.
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.
Attorney Leonard Leo of the Federalist Society, who is advising Trump on the process, said Blumenthal's remarks were "insulting and offensive". "And I expect we'll do that on sort of a normal timetable of a couple of months". As a judge on the US Court of Appeals in Washington he has written opinions on some of the nation's most sensitive issues.
He recently voiced disagreement with a court decision allowing an undocumented teenage immigrant to get an abortion. McConnell said he will push for a vote on the nomination before the November midterms. Kethledge, 51, is a judge for the Sixth Circuit Court of Appeals.