President Obama has nominated Merrick Garland, chief judge of the United States Court of Appeals for the District of Columbia Circuit, to fill the vacancy on the U.S. Supreme Court, but Republicans are not budging on their refusal to hold confirmation hearings.

Introducing Garland in the Rose Garden of the White House, Obama said Garland is one of the “sharpest legal minds” and “brings to his work a spirit of decency, modesty, integrity, even-handedness, and excellence.”

Garland, 63, originally from Chicago, was first appointed by President Clinton in 1997 to serve on the United States Court of Appeals for the District of Columbia, and was confirmed by the Senate for that role. 

Garland graduated from Harvard University in 1977, and served as a law clerk for then-Justice William Brennan of the U.S. Supreme Court from 1978 to 1979.

“I have fulfilled my constitutional duty.

Now it’s time for the Senate to do theirs.”

—@POTUS #SCOTUSnominee https://t.co/JNB1vTPy2x

— The White House (@WhiteHouse) March 16, 2016

“It was the beginning of a lifelong career — as a lawyer, and a prosecutor, and as a judge — devoted to protecting the rights of others,” Obama said. “And he has done that work with decency and humanity and common sense, and a common touch. And I’m proud that he’ll continue that work on our nation’s highest court.”

Garland thanked the president, calling the appointment “the greatest honor” of his life.

“As my parents taught me by both words and deeds, a life of public service is as much a gift to the person who serves as it is to those he is serving,” Garland said. “And for me, there could be no higher public service than serving as a member of the United States Supreme Court.”

Republicans have so far refused to hold any hearings on a nomination, citing the need for voters to have a voice by selecting a new president who would fill the seat. 

“The next justice could fundamentally alter the direction of the Supreme Court and have a profound impact on our country, so of course the American people should have a say in the Court’s direction,” Senate Majority Leader Mitch McConnell said Wednesday morning.

Iowa’s U.S. Sen. Chuck Grassley, chairman of the Senate Judiciary Committee, is playing a central role in the nomination fight. Grassley, who has also said he does not think the Senate should consider the nominee, has the power to hold any hearings as chairman of the Judiciary Committee.

“A lifetime appointment that could dramatically impact individual freedoms and change the direction of the court for at least a generation is too important to get bogged down in politics. The American people shouldn’t be denied a voice,” Grassley said in a statement Wednesday. “Do we want a court that interprets the law, or do we want a court that acts as an unelected super legislature? This year is a tremendous opportunity for our country to have a sincere and honest debate about the role of the Supreme Court in our constitutional system of government.”

U.S. Sen. Joni Ernst, R-Iowa, made similar comments, saying the fight is not about any specific nominee, rather giving a voice to voters.

“In the midst of a critical election, the American people deserve to have a say in this important decision that will impact the course of our country for years to come,” Ernst said. “We must wait to see what the people say this November, and then our next president will put forward a nominee.”

Former Iowa Lt. Gov. Patty Judge, a Democrat now running for Grassley’s U.S. Senate seat, said in a conference call with reporters Wednesday that Grassley should reconsider his position.

“He is the only person in Washington with the power to make hearings happen,” she said “For 35 years he has waited to become the chairman of the Judiciary Committee, now that he has the job he also has the power that comes with it. That power includes scheduling a hearing for Judge Garland.”

“He doesn’t need to wait for permission from his friends in the Republican leadership or Donald Trump, he could schedule and hold a hearing at his own discretion,” she added.

The Supreme Court vacancy comes after the death of Justice Antonin Scalia, who died in February.