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President Obama announced Wednesday that he is nominating federal appeals court judge Merrick Garland to the Supreme Court, praising his track record as a "thoughtful, fair-minded" jurist whose centrist bent has in the past appealed to congressional Republicans.

Related: Meet President Obama's Nominee to the Supreme Court

"Throughout his jurisprudence runs a common thread, a dedication to protecting the basic rights of every American, a conviction that in a democracy, powerful voices must not be allowed to drown out the voices of everyday Americans," Obama said from the White House Rose Garden, with Garland and Vice President Joe Biden at his side.

"To find someone with such a long career of public service marked by complex and sensitive issues, to find someone who just about everyone not only respects, but genuinely likes, that is rare," the president continued, "and it speaks to who Merrick Garland is not just as a lawyer, but as a man."

Meet Chief Judge Merrick Garland, the President's nominee to the Supreme Court. #SCOTUSnominee https://t.co/ACujysyyDJ — SCOTUS Nomination (@SCOTUSnom) March 16, 2016

Garland, the 63-year-old chief judge of the U.S. Court of Appeals for the District of Columbia Circuit, has nearly two decades on the bench, and as a federal prosecutor, oversaw the Oklahoma City bombing and "Unabomber" terror cases.

Garland is widely seen as a moderate, a reputation the White House likely hopes will help draw GOP votes during a Senate confirmation hearing. He was confirmed to the D.C. appeals court in 1997 with a 76-23 vote, winning backing from 30 Republicans.

Related: Poll Finds Majority Disapproves of GOP Plan to Block Nominee

At the time, Republican U.S. senator and Judiciary Committee member Orrin Hatch championed Garland's appointment to the federal appeals court, saying "his intelligence and his scholarship cannot be questioned."

Garland became that D.C. Circuit court's chief judge in 2013.

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But in this heated political climate, his nomination to the high court could be derailed as part of a protracted battle with congressional Republicans.

Senate Republicans have vowed not to take any action on Obama's pick to replace Antonin Scalia, one of the conservative stalwarts of the Supreme Court, after his death in Texas last month.

Senate Majority Leader Mitch McConnell reiterated that point on Wednesday. "The decision the Senate announced weeks ago remains about a principle not a person," he said.

The White House has said it is determined to press forward with the confirmation process. "He is the right man for the job. He deserves to be confirmed," Obama said Wednesday.

The president said Garland would begin touring Capitol Hill to meet with senators ahead of a potential hearing.

Garland became emotional as he spoke about learning he was Obama’s nominee, calling it the “greatest honor of my life” and the “greatest gift I’ve ever received” — second to marrying his wife and seeing the birth of his two daughters.

"There could be no higher public service than serving as a member of the United States Supreme Court," the Chicago-born Garland said.

As a judge, he said, "fidelity to the law" has always been a cornerstone to how he rules.

"People must be confident that a judge's decisions are determined by the law and only the law. For a judge to be worthy of such trust, he or she must be faithful to the Constitution and to the statutes passed by the Congress," he said. "He or she must put aside his personal views or preferences and follow the law — not make it."

Garland graduated first in his class at Harvard University before attending Harvard Law School, where he earned magna cum laude honors in 1977.

He clerked for Supreme Court Justice William J. Brennan, and later, as principal associate deputy attorney general for the Justice Department, he helped put away Oklahoma City bombers Timothy McVeigh and Terry Nichols and "Unabomber" Ted Kaczynski.

Obama said Garland never forgot about the victims of Oklahoma City, carrying on his person a program from a memorial service with all 168 names of those killed in the horrific 1995 bombing.

"It’s no surprise, then, that soon after his work in Oklahoma City, Merrick was nominated to what’s often called the second-highest court in the land, the D.C. Circuit Court," Obama said.

Scalia, who died Feb. 13, was one of the key right-leaning voices on the court; with his death, the court is split 4-4 between liberals and conservatives. Garland, if confirmed, could tilt the court to the center-left for the first time in decades.

Garland at age 63 would be among the oldest nominees for the high court, which could prove to be another roadblock to the Supreme Court. Justices have typically been in their 50s when they’ve been confirmed, ensuring they remain on the bench for a long time.

But Obama gave a stern warning for the GOP to take up the issue — the last time a Supreme Court nominee was denied a vote was in 1875, the administration said.

"To suggest that someone as qualified and respected as Merrick Garland doesn’t even deserve a hearing, let alone an up or down vote ... that would be unprecedented," Obama said. "To suggest that someone who has served his country with honor and dignity, with a distinguished track record of delivering justice for the American people might be treated — as one Republican leader stated — as a political pinata. That can’t be right."