The members of Vermont's congressional delegation condemned Tuesday's U.S. Supreme Court decision that upholds a ban on travel from five Muslim-majority countries. He has sided with the liberal justices on gay rights and abortion rights, as well as some cases involving race, the death penalty and the rights of people detained without charges at the Guantanamo Bay naval base.
A lawsuit filed in March says the administration's decision to end temporary protected status was motivated by racism, citing Trump's vulgar language during a meeting in January to describe African countries.
Kennedy has always been considered the swing vote on the court between the liberal and conservative justices.
For months, Kennedy had teased his retirement, but it was unclear whether he would officially pull the trigger over concerns about who President Trump might appoint to replace him.
The Supreme Court's ruling will likely prompt the administration to argue that courts should be just as deferential to the president's other immigration policies, so it's not a complete victory for plaintiffs in other suits, said Stephen Yale-Loehr, a professor of immigration law practice at Cornell Law School.
Trump praised Kennedy as a man of "tremendous vision" and said his search for a new justice would begin "immediately".
To figure out how Trump's nominee might transform the court's ideological makeup, we looked at potential candidates' Judicial Common Space scores, which measure judicial ideology relative to the full court, the president and Congress.
That will give President Donald Trump the chance to cement conservative control of the high court. Most notably, he wrote the 2015 ruling on Obergefell v Hodges, which found that a ban on same-sex marriage was unconstitutional.
"If a vacancy occurs during this term, after the Garland heist, the balance of the court could be tilted even more against women's, workers', and civil rights for decades to come by the president's list of 25 judges who have passed his litmus test of overturning Roe v. Wade", Democratic Sen.
Arizona Senator Jeff Flake questioned the wisdom of the policy, though he agreed with the Supreme Court that the policy is constitutional. "The most important thing we can do".
But picking an ultra-conservative as his nominee would carry risk because Trump would have to rely on some moderate Republicans to win approval in the U.S. Senate, where his fellow Republicans have a narrow majority.
Justice Kennedy, 81, will retire on 31 July, per his letter to Mr Trump.
Trump picked Gorsuch from a list of names, mostly conservative federal appeals court judges, he circulated during his 2016 election campaign.