However, Senate Republicans, who control the chamber, have vowed not to hold confirmation hearings or a vote on any nominee picked by the Democratic president for the lifetime position on the court.
President Barack Obama nominated veteran appellate court judge Merrick Garland to the US Supreme Court on Wednesday, setting up a potentially ferocious political showdown with Senate Republicans who have vowed to block any Obama nominee.
Considered a moderate, Garland, 63, is currently chief judge of the US Court of Appeals for the District of Columbia. He was picked to replace long-serving conservative Justice Antonin Scalia, who died on February 13.
Speaking in the White House Rose Garden as his administration girded for a fight, Obama urged Senate Republicans to consider the nomination, saying faith in the American justice system was at stake.
"I've selected a nominee who is widely recognised not only as one of America's sharpest legal minds but someone who brings to his work a spirit of decency, modesty, integrity, even-handedness and excellence," Obama said.
"These qualities and his long commitment to public service have earned him the respect and admiration of leaders from both sides of the aisle (Democrats and Republicans)."
Senate confirmation is required for any nominee to join the bench and Scalia's sudden death set off an election-year fight well before Obama made his choice.
Republicans, hoping a candidate from their party will win the November 8 presidential election, are demanding that Obama leave the seat vacant and let the next president, to be sworn in next January, make the selection.
Senate Republicans, who control the chamber, have vowed not to hold confirmation hearings or a vote on any nominee picked by the Democratic president for the lifetime position on the court.
Obama said on Wednesday that if Senate Republicans refused to carry out their constitutional function to consider Garland's nomination, the reputation of the Supreme Court and faith in the American justice system would suffer.
"Our democracy will ultimately suffer as well," Obama added.
"I have fulfilled my constitutional duty. Now it's time for the Senate to do theirs. Presidents do not stop working in the final year of their term. Neither should a senator," added Obama.
He said he hoped the Senate would vote to confirm Garland in time for him to join the court when it gets to work for its 2016-1017 term in October, adding Garland would start meeting with senators one-on-one on Thursday.
Garland is a long-time appellate judge and former prosecutor who Obama also considered when he filled two previous Supreme Court vacancies.
'Words and deeds'
Standing in between Obama and Vice President Joe Biden during the Rose Garden ceremony, Garland told Obama it was a great privilege to be nominated to the high court by a fellow Chicagoan.
"(A) life of public service is as much a gift to the person who serves as it is to those he is serving. And for me there could be no higher public service than serving as a member of the United States Supreme Court," said Garland, who would become the fourth Jewish member of the nine-member court.
In a foreshadowing of the pressure campaign the White House and its allies plan to wage in the coming weeks, the White House noted that seven current Republican US senators voted to confirm Garland to the DC Circuit court in 1997.
Garland, who has earned praise from lawmakers of both parties in the past, was named to his current job by Democratic President Bill Clinton in 1997, winning Senate confirmation in a 76-23 vote. Prior to that, he worked in the Justice Department during the Clinton administration.
Federal appeals court judge Sri Srinivasan had also been a finalist for the nomination.
Without Scalia, the nine-member Supreme Court is evenly split with four liberals and four conservative justices. Obama's nominee could tilt the court to the left for the first time in decades.
Republicans are hoping to keep the vacancy until the new president takes office, and hoping their candidate wins.
Currently, billionaire Donald Trump is the leading Republican presidential candidate while Obama's former secretary of state, Hillary Clinton, is the front-runner on the Democratic side.
Republicans and their allies already have geared up to fight Obama's nominee. The Republican National Committee on Monday announced the formation of a task force that will work with an outside conservative group to spearhead attack ads and other ways of pushing back against Obama's choice.
The US Court of Appeals for the District of Columbia Circuit has served as a springboard to the Supreme Court for several justices including Scalia in recent decades.
Obama may have been looking for a nominee who could convince the Republicans to change course. Garland could fit that bill with his moderate record, background as a prosecutor and history of drawing Republican support.
Garland was under consideration by Obama when he filled two prior high court vacancies. Obama, in office since 2009, has already named two justices to the Supreme Court: Sonia Sotomayor, who at 55 became the first Hispanic justice in 2009, and Elena Kagan, who was 50 when she became the fourth woman ever to serve on the court in 2010.
Presidents tend to pick nominees younger than Garland, so they can serve for decades and extend a president's legacy. But Obama may reason that the choice of an older nominee might also entice Senate Republicans into considering Obama's selection.