Count state Auditor Hector Balderas among the candidates for the U.S. Senate seat that fellow Democrat Jeff Bingaman plans to vacate next year.

Balderas filed a statement of candidacy with the Federal Election Commission and formally will announce his candidacy next week, a source close to Balderas said Thursday.

Balderas, 37, will face at least one other candidate in next year's Democratic primary: U.S. Rep Martin Heinrich of Albuquerque.

The news of Balderas' FEC filing came shortly after the political committee of the largest public employee union — the American Federation of State, County and Municipal Employees — voted unanimously to endorse Heinrich.

Heinrich recently jumped in the race after Bingaman, a senator since 1983, announced that he won't be seeking re-election next year.

Balderas is from the small northeastern New Mexico community of Wagon Mound. A lawyer by profession, he was elected to a state House of Representatives seat in 2004, defeating a Democratic incumbent, Benjie Regensberg.

Just two years after that election, the state Democratic Party Central Committee nominated Balderas for the auditor position after the candidate who had won the party's primary election was forced off the ticket following revelations of alleged sexual misconduct.

Although the office of auditor traditionally has been a low-profile agency, Balderas was aggressive in using the power of subpoena to uncover cases of alleged fraud.

His audits of the Secretary of State's Office and Regional Housing Authority helped uncover evidence later used in indicting former Secretary of State Rebecca Vigil-Giron and Region III Housing Authority director Vincent "Smiley" Gallegos. (Both former officials have yet to be tried and both have pleaded not guilty.)

Balderas also helped uncover embezzlement from the Jemez Mountain School District involving more than $3 million. A finance manager for the school system pleaded guilty to multiple felonies and then killed herself before she was sentenced.

Balderas was re-elected to the auditor's job last year.

Heinrich, who announced his candidacy last month, has been considered the front-runner in the Democratic primary. According to FEC records, he has nearly $350,000 in campaign funds, while Balderas, who has never run for federal office, has not yet raised any money for the race. (State candidates aren't allowed to use money raised in state races to seek election to federal positions.)

The AFSCME endorsement is bound to help with Heinrich's fundraising effort. The union is a major contributor to Democratic campaigns. According to the Institute of Money in State Politics, AFSCME contributed more than $435,000 to candidates in New Mexico.

Heinrich, a former Albuquerque city councilor, also has been endorsed by the Teamsters Union.

He was first elected to Congress in 2008 after Republican Heather Wilson decided to run for an open Senate seat. He was re-elected last year.

Also in the Senate race on the Democratic side is Albuquerque activist Andres Valdez.

Wilson, who served 10 years in Congress, is running in the GOP primary for Bingaman's seat. Two lesser-known Republicans, Greg Sowards and Bill English, also have declared their candidacies.

Lt. Gov. John Sanchez, also a Republican, has said he's considering running, as has U.S. Rep. Steve Pearce of Hobbs. Pearce won the Republican nomination in 2008 after a bitter competition with Wilson. Democrat Tom Udall won the general election that year.

Contact Steve Terrell at 986-3037 or sterrell@sfnewmexican.com. Read his political blog at roundhouseroundup.com.