He announced his Senate bid Monday on Twitter, touting his record on voting rights and consumer protection while criticizing the Senate's Republican majority leader. "To move forward, we've got to fix the Senate where Mitch McConnell stands in the way of progress," Luján said.
Luján is the first politician to declare his candidacy for the Senate seat. A former chairman of the Democratic Congressional Campaign Committee, Luján first won election when Barack Obama was elected president in 2008, supporting Obama's recession-era stimulus package and health care overhaul.
In a conversation with The Associated Press on Monday, Luján emphasized the importance of Democratic efforts to defend access to health insurance "no matter how much money you make or what area code you live in."
"We're working to strengthen the Affordable Care Act and address all the sabotage we've seen from House Republicans, Senate Republicans as well as the Trump administration," said Luján, who has sponsored legislation that would allow a buy-in option for Medicaid coverage for those who don't otherwise qualify.
Trump last week revived the fight over the Affordable Care Act in declaring that the "Republican Party will soon be known as the party of health care." Luján readily won reelection in recent years while campaigning to advance immigration reform, combat climate change and address the state's crisis of opioid addiction and drug overdose deaths.
Luján is a close ally of House Speaker Nancy Pelosi and this year seized a coveted seat at the leadership table as the assistant speaker. Pelosi all but endorsed the decision to run for Senate. When Luján entered the Democrats' regular leadership meeting last week after Udall's announcement he would retire, Pelosi welcomed him as "Senator Luján," according to a person granted anonymity to discuss the private session.
Luján currently holds the northern New Mexico congressional seat that was a political stepping stone for Udall and Democrat Bill Richardson — the former governor, U.S. Cabinet secretary and U.N. ambassador. Udall left the House of Representatives in 2008 when he succeeded Republican Pete Domenici in the Senate.
Luján hails from a prominent New Mexico political family that includes Gov. Michelle Lujan Grisham, a distant cousin by marriage, as well as his father, Ben Luján, who was the state's House speaker for over a decade. The elder Luján served in New Mexico's unsalaried Legislature from 1974 until shortly before his death in 2012.
In Monday's video announcement, the 46-year-old Lujan described his parents' working class ties as a union iron worker and a retired local school teacher. A conservative-leaning watchdog group filed an ethics complaint in 2015 that accused Luján of utilizing the House chamber to raise money for campaign purposes, citing the use of photos from a sit-in against gun violence in solicitation emails. The House Ethics Committee found no violation of rules and said the emails were sent by a campaign consultant without evidence that Luján was aware.
Luján said Monday that the inquiry showed no infraction from the emails that emerged from a group event. "There was someone on the (outside) team that made that decision to move forward with a fundraising email," he said.
Some of the state's prominent Democratic office-holders already have indicated they will not compete for the Senate seat. New Mexico Attorney General Hector Balderas last week ruled out a Senate bid, citing personal and professional reasons, and Albuquerque Mayor Tim Keller has said he is focused on his current job. No Republican has entered the race.
Associated Press writer Lisa Mascaro contributed to this report from Washington.