Thomas Stewart Udall (/ˈjuːdɔːl/ YOO-dawl; born May 18, 1948) is an American diplomat, attorney, and politician who had served as the United States Ambassador to New Zealand and Samoa.

On July 16, 2021, President Joe Biden nominated Udall to serve as United States Ambassador to New Zealand and Samoa.

[citation needed] As a U.S. Representative, Udall was a member of both the centrist New Democrat Coalition and the more liberal Congressional Progressive Caucus.

He was a member of the United States House Peak oil Caucus, which he co-founded with Representative Roscoe Bartlett of Maryland.

[citation needed] In November 2007, Udall announced his run for the Senate seat held by retiring six-term incumbent Republican Pete Domenici.

[12] Udall was one of the first members of Congress to publicly express concern about the possibility of NSA overreach, a year before Edward Snowden's 2013 disclosure of the PRISM program.

[16][17] Also during the 113th Congress, Udall introduced a proposed amendment to the Constitution that would reverse Citizens United and allow limits on outside spending in support of political candidates.

[19] In December 2014, Udall introduced a resolution condemning the Indonesian mass killings of 1965–66 and calling for the declassification of documents on United States involvement in the genocide.

[24][25] The bill initially faced criticism over the balance between federal and state authority to regulate chemicals, but after changes to the legislation, it earned broader support, including from liberal members of the Senate and the President.

"[38] In late 2019, Udall co-sponsored the Green New Deal, a policy introduced in the U.S. Senate that would establish net-zero carbon emissions by 2050.

[39] On July 16, 2021, President Joe Biden nominated Udall to serve as United States Ambassador to New Zealand and Samoa.

[43] On February 17, 2022, he virtually presented his credentials to the Head of State of Samoa, Afioga Tuimalealiʻifano Vaʻaletoʻa Sualauvi II.