SANTA FE, N.M. - When he became New Mexico's governor in 2003, Bill Richardson - former energy secretary, U.N. ambassador, and freelance diplomat - vowed to shake up this sleepy state.

Richardson cut taxes and revamped energy regulations. He gave raises to teachers, and driver's licenses to illegal immigrants. He legalized medical marijuana and suspended the death penalty.

In 2006, he won reelection by a 2-1 margin. Then he sought the 2008 Democratic presidential nomination, leading many to believe he could become the first Latino president or vice president.

But now, Richardson's approval rating is in the low 30s. His handpicked successor, Lt. Gov. Diane Denish, was trounced in November. Her Republican opponent tied her to the unpopular governor so often that Denish ran an ad noting Richardson was not on the ballot. And as Richardson cleared out his office, the most momentous decision left for this onetime giant on the national stage was whether to issue a posthumous pardon to Billy the Kid.

"It's been like one of those elevators where they cut the cord from the 60th floor," said Joe Monahan, a respected New Mexico political blogger who carefully tracked Richardson's career. "Second terms are rough."

Richardson, 63, is one of a long line of elected officials who came in with a bang only to exit with a whimper, laid low by the economy.

He also was wounded by a federal investigation into whether a financial-services firm donated to his political committees to win a bond contract. No charges were filed against him or his staff, but the controversy tarnished his image.

In an interview shortly after returning from an unofficial diplomatic foray to North Korea, Richardson said he would stay in New Mexico and start a nonprofit institute for international peacekeeping.

He allowed that his relentless style may have worn out the public. "People get tired of politicians," he said. "I've been around eight years."

Born in Pasadena, Calif., Richardson is named after his father, an investment banker who married a member of Mexico City's elite while working there. Richardson grew up partly in Mexico and partly in New England. In 1980, he ran for a seat in Congress from New Mexico and lost, but he won two years later.

In the 1990s, he caught the eye of President Bill Clinton, who tapped him to travel to Iraq and negotiate the release of two American aerospace workers held by Saddam Hussein. He also went to North Korea, where he secured the release of an American. Clinton then appointed him as U.N. ambassador and later as energy secretary.

When Clinton left office in 2000, Richardson turned his ambitions to the governorship, winning easily.

"He was good at making things happen," said Lonna Atkeson, a political science professor at the University of New Mexico. "He was willing to take positions on issues - some of them controversial."

Richardson made little secret that he wanted to run for president. But in 2008, "the people wanted Obama," Richardson said. "They wanted inspiration, not resumé."

When the governor finished fourth in the Iowa caucuses and the New Hampshire primary, he withdrew and endorsed Barack Obama - a shock, given Richardson's long association with the Clintons.

After the election, Obama tapped him as commerce secretary but later asked Richardson to take himself out of the running after the administration learned more about the federal probe into New Mexico's bond deals.

Republican Susana Martinez won the governorship by 7 points. Observers expect her and the state GOP to try to reverse some of Richardson's initiatives, such as driver's licenses for illegal immigrants.

Richardson, however, said he expected his legacy to survive because Democrats still control the state Legislature. He ticked off a list of achievements, including sometimes-quixotic efforts to revive the perennially impoverished state, such as a spaceport to launch tourists into orbit.

"Was I hyperactive?" Richardson said. "Yes. Did I try to do too much? No. There was a lot to do."