Updated

Mississippi Republican Trent Lott officially resigned from the U.S. Senate on Tuesday, ending a 35-year career in which he reached the of height of power before falling from grace and climbing his way back to the top, a spokesman said.

Lott, 66, had announced in his home state Nov. 26 that he would step down by year's end, saying he wants to pursue other opportunities. He submitted the paper work Tuesday to make it official, his spokesman, Lee Youngblood, told The Associated Press.

"U.S. Sen. Trent Lott has informed Vice President Dick Chaney, the president of the U.S. Senate, that he is retiring as the U.S. Senator for the state of Mississippi effective on the close of the Senate's business today, Tuesday Dec. 18, 2007," Youngblood said.

Youngblood announced the resignation about 10:45 p.m. CDT. He said the resignation came so late because Lott had to resign the day before the Senate recesses, likely Wednesday, but he wanted to vote on important bills that were being considered well into the night.

Saying farewell to Washington colleagues earlier in the day, Lott drew upon his modest background as the son of a Gulf Coast shipyard worker.

"We had a class motto that has lived with me since those years at Pascagoula High School in 1959. ... 'The glory is not in never failing, but in rising every time you fail,"' Lott said during a ceremony on the Senate floor in Washington.

"I've had opportunities to fail and I've had opportunities to persevere," he said in remarks broadcast on C-SPAN2.

Lott resigns with five years left in his current six-year term. He served 16 years in the U.S. House before moving to the Senate in 1988.

Gov. Haley Barbour will appoint a successor to serve until a special election is held next year. The timing of the special election is in dispute. Barbour, a Republican, said he plans to set it for Nov. 4, but state Attorney General Jim Hood, a Democrat, issued a nonbinding opinion this week that the election must be held within 100 days of Lott's departure.

Lott — a neat-haired perfectionist with a penchant for order — rose to the pinnacle of Washington politics as Senate majority leader but was ousted from the post in 2002 over remarks he made at retiring Sen. Strom Thurmond's 100th birthday party that were interpreted as support for Southern segregationist policies. President Bush did not stand behind Lott after his remarks about Thurmond, increasing pressure on the lawmaker to step down from the leadership post.

Lott became Republican whip last year — a job that let him exercise his vote-counting skills.

Sen. John Warner, R-Va., praised Lott Tuesday for "your magnificent and courageous restoration of your career in full."

Lott has not said what kind of job he'll pursue. There's widespread speculation that he might enter the lobbying business with one of his longtime friends, former Sen. John Breaux, a conservative Democrat from Louisiana.

Lott said last month that new restrictions on lobbying that take effect after Dec. 31 "didn't have a big role" in his decision to retire. The regulations extend the "cooling off" period for lobbying by former members of Congress from one to two years.

During the Senate floor ceremony, Sen. Patrick Leahy, D-Vt., praised Lott as a colleague who keeps his word and works across party lines.

"I don't want to damage his reputation in Mississippi to have one of the more liberal members of the opposite party praise him," Leahy joked.

Sen. Saxby Chambliss, R-Ga., said Lott is "the epitome of the genteel Southern gentleman."

Mississippi's senior U.S. senator, Republican Thad Cochran, recalled in a written statement how he and Lott were both elected to the House in 1972; each was the first Republican elected from his district since Reconstruction. Cochran moved to the Senate in 1978.

"I have come to respect him and appreciate his legislative skills and his great capacity for hard work," Cochran said. "He is a tireless and resolute advocate for causes and issues which he decides to support. In a word, he is a winner. He gets things done."

In announcing his retirement, Lott said he had not planned to seek re-election in 2006, but he changed his mind after Hurricane Katrina devastated Mississippi's Gulf Coast and demolished his beachfront home in Pascagoula.

Barbour — a former Republican National Committee chairman — has not said who he'll appoint to succeed Lott. Among the Republicans whose names are circulating as possibilities are U.S. Reps. Roger Wicker and Chip Pickering and Gulfport Mayor Brent Warr.

Lott was the sixth Senate Republican this year to announce retirement. Democrats effectively hold a 51-49 majority in the chamber, including two independents who align themselves with Democrats. Lott's retirement means that Republicans will have to defend 23 seats in next year's election, while Democrats have only 12 seats at stake.

Lott ruled out any health concerns in his departure, but he said it's time for a younger voice to represent Mississippi in the Senate.

Lott said Tuesday that he is proudest of having helped write balanced budgets while he was majority leader during the 1990s. He said his biggest regret is leaving while the future of Social Security appears shaky.

"I have no anger or complaints. I have nothing but hope and joy in my heart for the future," Lott said. "I am so appreciative of the way the Senate and the Congress and the American people stepped up and helped us after Hurricane Katrina."

Youngblood said Lott has about 40 staff members in Washington and in three Mississippi offices. He said Senate rules allow them to keep their jobs for up to 60 days after Lott leaves office.