Supreme Court Justice Sonia Sotomayor says Justice Anthony Kennedy was passionate about the Constitution and the court.
"It is undeniable that he has had a monumental effect on the law," she said in a statement.
She continued: "I have witnessed his love and dedication to his family and know that he will cherish spending more time with them. I will miss working with him dearly, but I know he will continue to be a roaring lion, even as he takes senior status."
Justice Elena Kagan also weighed in on Kennedy's retirement.
Retired Supreme Court Justice John Paul Stevens described his disappointment over Justice Anthony Kennedy's decision to retire because he said the jurist "will not be easily replaced."
"Tony Kennedy was, and is, a close friend," Stevens said. "We have retained that close friendship since my retirement, and I continue to admire his independence, the high quality of his judicial work, and his devotion to the mission of the court."
"I am, of course, disappointed by his decision to retire for he will not be easily replaced, but he has certainly earned the right to enjoy a more leisurely life without the constant burden of reading briefs. I wish him and Mary all the best."
Supreme Court Justices Samuel A. Alito and Stephen G. Breyer said they will miss working with Justice Anthony Kennedy, who announced his retirement on Wednesday.
Breyer also described Kennedy as "a judge of great vision."
"His knowledge of the Constitution is profound," Breyer said. "He is thoughtful and careful in his decision-making, and he has made it a great pleasure for all of us to work together with him."
Supreme Court Justice Ruth Bader Ginsburg, who has served on the bench for 25 years, described Justice Anthony Kennedy as a "caring jurist."
In a statement, she said she'll miss Kennedy's company and recommendations for art exhibitions to see.
"Justice Kennedy is a true gentleman, a caring jurist, and a grand colleague in all respects," he said. "I will miss the pleasure of his company at our Conference table, his helpful suggestions on circulating opinions, his recommendations of art exhibitions to visit with my chambers staff, and much more."
Supreme Court Justice Neil Gorsuch praised Justice Anthony Kennedy for his years of service on the bench.
Gorsuch, who worked as Kennedy's law clerk 25 years ago, said in a statement that Kennedy was a "model of civility, judicial temperament, and kindness."
Read his statement:
For more than forty years, Justice Kennedy has served the Judiciary and the Nation with unfailing integrity and immense wisdom. He is a model of civility, judicial temperament, and kindness. His respect for every person and every case has made him a great man and a great judge. It was the honor of a lifetime to serve as his law clerk 25 years ago, and it has been an unexpected joy to serve this year as his colleague. I also want to extend my gratitude to the Justice’s wife, Mary. Her graciousness has left an indelible mark on my family and everyone she touches. I wish the Justice and Mary, and their wonderful family, every happiness in the years ahead.
The Republicans’ goal — as of now — is to hold a confirmation hearing for a new Supreme Court nominee around Labor Day, a congressional source told CNN.
The goal is to get the nominee in place for the start of the fall term, which begins the first Tuesday in October, the source said.
Chief Justice John G. Roberts Jr. said Supreme Court Justice Anthony Kennedy brought "wise counsel" through his teachings on the rule of law.
In a statement, he said Kennedy's "jurisprudence prominently features an abiding commitment to liberty and the personal dignity of every person."
"Justice Kennedy taught collegiality and civil discourse by example," Roberts said.
Supreme Court Justice Clarence Thomas described Justice Anthony Kennedy as a "wonderful colleague" and "consummate gentleman."
In a statement, Thomas said Kennedy has been "unfailingly civil and Kind" to his fellow Supreme Court justices.
Here's Thomas' full statement:
I am deeply, deeply saddened to see Justice Kennedy leave the Court. We have been colleagues here at the Court for over a quarter of a century. Throughout that time, he has been a consummate gentleman and a wonderful colleague. And, he has been unfailingly civil and kind in all of his interactions with each of his colleagues. Even during the most difficult and challenging times, he had a way of elevating each of us by his example. He is a good man who will be remembered not only for a long and productive career on the bench but also for the way he conducted himself. It is an honor to have served on the Court with him and to know him as a friend. Virginia and I wish him and Mary nothing but the best.
The court opening is likely to drastically alter both parties' approaches to November's midterm elections. Republicans, in particular, hope the vacancy activates a base that the party has worried would sit out this year's contests.
The timing couldn't be worse for the five Democratic senators up for re-election in states Trump won by double digits: Sens. Joe Donnelly of Indiana, Claire McCaskill of Missouri, Jon Tester of Montana, Heidi Heitkamp of North Dakota and Joe Manchin of West Virginia.
If those five vote against Trump's nominee, they'll hand Republicans a potent issue to hammer them with. If they vote for the nominee, they risk severe retribution from within the Democratic Party.