Rep. Martin HeinrichMartin Trevor HeinrichHillicon Valley: AT&T calls hiring Cohen a 'big mistake' | Wyden wants to block DHS nominee over Stingray surveillance | Amazon pressed on child privacy | One year anniversary of Trump cyber order Moment of truth for Trump pick to lead CIA Puerto Rico's electric grid under scrutiny as new hurricane season looms MORE (D-N.M.) announced Saturday that he will run for the Senate seat being vacated by Democratic Sen. Jeff Bingaman.

"After much serious thought, I am excited to announce today that I will be a candidate for the United States Senate," Heinrich said in a letter to supporters.

"I would be proud to represent you in the U.S. Senate.  I hope you’ll join me on this journey to provide everyone in this state with a prosperous future worthy of our efforts and our values."

Heinrich's campaign also released a video that features him in what appears to be his family's Albuquerque home. He speaks into the camera about his reasons for entering the race and his monologue is interlaced with footage of the congressman cooking with his wife, and his son feeding chickens in a coup behind the house.

Heinrich, who represents New Mexico's 1st Congressional District, is in his second term in the House. Bingaman, who announced in February he wouldn't seek reelection in 2012, has held the Senate seat since 1982.

After his announcement, New Mexico GOP Chairman Monty Newman called Heinrich a "partisan politician."
“New Mexican voters want a senator who will represent the best interests of hard working, taxpaying New Mexican families and not another partisan politician like Martin Heinrich," Newman said in a statement.

The National Republican Senatorial Committee immediately labeled Heinrich a "liberal."

“A big problem for Martin Heinrich is that there is a mile-wide gap between his moderate rhetoric versus his very liberal record," an NRSC spokesman said in a statement. "Heinrich has consistently voted with the liberal wing of his party, helping his Democrat bosses ram through their massive health care overhaul, their job-killing cap-and-trade energy tax, and their failed $787 billion stimulus debacle."

The NRSC will likely seek to soften Heinrich up with attacks on his record while it waits for the GOP nominee to emerge from what could be a four-way primary. The field now includes former Rep. Heather Wilson (N.M.), businessman and former congressional candidate Greg Sowards and Bill English. Lt. Gov. John Sanchez told The Hill in a recent interview that he plans to reveal "relatively soon" whether he'll also seek the nomination.

"We think that sometime here in the near future, in the spring, we'll be making a final decision as far as what our intentions are," he said in an interview where he dismissed Wilson as a "moderate-type."

Heinrich is the first major Democrat to declare. He'll face Albuquerque political activist Andres Valdez (D), who announced in February that he intends to run for the seat, in the primary.

This post was updated at 5:33 p.m.