U.S. Sen. Patrick Leahy endorsed Barack Obama for president Thursday, saying the Illinois senator is the candidate who can best "express America's values."

The Vermont Democrat and chairman of the Senate Judiciary Committee is the latest high-powered senator to close ranks behind Obama after his Jan. 8 loss to Hillary Clinton in New Hampshire. Massachusetts Sen. John Kerry, who was the 2004 Democratic presidential nominee, announced his support shortly after the Granite State primary.

"We need a president who can reintroduce America to the world and actually reintroduce America to ourselves," Leahy said in a conference call with reporters. "I believe Barack Obama is the best person to do that."

He stressed the need for hope in order to end the Iraq war, education improvements and expanded health care.

"Barack Obama gives us that hope and I'm convinced he can lead our country to achieve those goals," Leahy said. "Barack Obama represents the America we once were and want to be again, leading with hope and opening the doors of opportunity for everyone."

Leahy, a six-term senator, has been a vocal critic of the Iraq war and as the current Judiciary Committee chairman, has been at the forefront of the battle over Supreme Court nominations.

Leahy went through an ideological clash over Robert Bork's failed nomination in 1987 and grilled Justice Clarence Thomas during his 1991 confirmation hearing. More recently Leahy, 65, has opposed several of President Bush's nominees, including withdrawn federal judge candidate Terrence Boyle and confirmed Supreme Court Justice Samuel Alito.

FOX News' Major Garrett and The Associated Press contributed to this report.