By Will Dunham

WASHINGTON Bill Richardson, a former U.S. diplomat, congressman, energy secretary and New Mexico governor who made his mark on the world stage by securing the release of Americans and others held by various autocratic governments, has died at the age of 75, the Richardson Center for Global Engagement said on Saturday.

Richardson, who made an unsuccessful 2008 bid to become the first Hispanic U.S. president, passed away in his sleep at his summer home in Chatham, Massachusetts, vice president of the Richardson Center Mickey Bergman said in a statement.

"The world has lost a champion for those held unjustly abroad and I have lost a mentor and a dear friend," said Bergman.

The son of a Mexican mother and an American father, Richardson served from 1982 to 1996 as a Democratic member of the U.S. House of Representatives, then as U.S. ambassador to the United Nations and energy secretary, both under President Bill Clinton. Richardson was elected as governor of New Mexico, serving from 2003 to 2011.

Using deft negotiating skills and personal warmth, he was able both as a formal representative of the United States and as a freelance troubleshooter on private humanitarian missions to win the release of numerous people held in nations including North Korea, Myanmar, Sudan, Iraq, Iran and Cuba.

"The first rule of negotiating, with me, is you've got to relate to your adversary personally. You have to respect them. You've gotta know what ... makes them tick," Richardson said on a podcast produced by Foreign Policy magazine in 2018. "You've gotta let the other side save face and find some ways that they get some credit, that they're getting something out of the negotiation, when in effect the only thing may be praise for a humanitarian gesture."

Richardson, while serving as New Mexico governor, sought the 2008 Democratic presidential nomination but dropped out after disappointing finishes in key early voting contests in New Hampshire and Iowa.

Barack Obama, who won the nomination and later the presidency, considered Richardson as a possible vice presidential running mate. Obama in 2009 nominated Richardson as U.S. commerce secretary but he withdrew due to an investigation into whether his aides in New Mexico had steered lucrative contracts to a political donor - a probe that was later dropped without any charges being pursued.

Richardson's willingness to meet with notorious foreign leaders sometimes drew criticism, as was the case in 2021 when some human rights activists accused him of giving Myanmar's junta legitimacy with such a meeting. Two weeks later, Myanmar released American journalist Danny Fenster from prison upon Richardson's urging.

As a congressman in 1994, Richardson visited reclusive communist-ruled North Korea to discuss a nuclear accord struck by Clinton. As Richardson was traveling to the country, North Korea shot down a U.S. military helicopter that had entered its territory, killing one pilot and capturing the other. Richardson stayed for weeks to negotiate, flying home with the dead pilot's remains while the surviving pilot was released soon thereafter.

In 1996, Richardson negotiated the release of an American named Evan Hunziker, jailed on spy charges in North Korea. Richardson later secured the remains of American troops missing since the Korean War of the 1950s and was involved in efforts to win the release of other Americans held by North Korea.

Richardson negotiated personally with Iraqi President Saddam Hussein in 1995 to gain the release of two American aerospace workers who had strayed over the Iraqi border from Kuwait. When Richardson reached over to pat Saddam on the arm after securing the deal, the Iraqi leader's security guards misunderstood the friendly gesture and reached for their guns.

He held personal talks with President Fidel Castro in 1996, facilitating the release of three Cuban political prisoners, who then were reunited with relatives in Miami.

William Blaine Richardson was born in Pasadena, California, on Nov. 15, 1947. He spent part of his youth in Mexico City, where his bank executive father headed Citibank and his mother, who was born in Oaxaca and had worked as a bank secretary, were a leading society couple. Richardson later attended a prep school in Massachusetts, where he became a star baseball pitcher with dreams of a professional career.

Richardson earned undergraduate and master's degrees from Tufts University, then moved to Washington and worked at the State Department and as a congressional staffer. After relocating to New Mexico, he won a seat in the U.S. House in 1982, launching his career as an American public figure.

(Reporting by Will Dunham in Washington, additional reporting by Lucia Mutikani; Editing by Rosalba O'Brien)