Pietro "Pete" Domenici, the well-regarded New Mexico Republican who spent 36 years in the U.S. Senate, stunned many observers this week when he admitted to fathering a child outside his marriage more than 30 years ago with the daughter of his former Senate colleague Paul Laxalt.

Domenici, now 80, retired from the Senate at the end of 2009 after finishing his sixth term—a move he said in 2007 he was planning to make as a result of his suffering from a degenerative brain disease. Though it took some by surprise, Domenici’s announcement that he was leaving office pales next to the bombshell he shared with the Albuquerque Journal this week.

Acting at least in part on a belief that someone else was poised to spill his secret, Domenici told New Mexico’s largest newspaper that he is the father of noted GOP lobbyist Michelle Laxalt‘s son, Las Vegas lawyer and Lewis and Roca litigation of counsel Adam Paul Laxalt. The younger Laxalt, a former U.S. Navy officer and judge advocate general who served in Iraq, has written columns espousing conservative causes for several publications. He did not respond to The Am Law Daily‘s request for comment on Domenici’s revelation.

Paul Laxalt, a 90-year-old Nevada Republican who currently divides his time between northern Virginia and Lake Tahoe, spent 12 years in the Senate before retiring in 1986 to become a partner at Finley, Kumble, Wagner, Underberg, Manley, Myerson & Casey, according to a 1987 New York Times story. Finley Kumble, of course, collapsed in spectacular fashion in 1987, and Laxalt went on to form 100-lawyer Laxalt, Washington, Perito & Dubuc. He left that firm in 1990 to form his own government relations shop.

Michelle Laxalt, who was 24 when she and the then-50-year-old Domenici conceived their child, said in a statement to the Albuquerque Journal that she chose to raise her son as a single mother and made Domenici pledge never to reveal himself as the father.

She told the newspaper that the pair chose to treat what she described as "one night’s mistake that led to pregnancy 30 years ago" as a private matter, and only decided to go public with their secret now because they believed someone was going to use it to "smear, hurt, and diminish Pete Domenici, an honorable man, his extraordinary wife, Nancy, and other innocents."

Domenici, who continues to live in Washington, D.C., expressed regret over his behavior and admitted that his wife had only recently learned about the long-ago tryst. Domenici said in a prepared statement that he alone "should bear the brunt of this matter" and asked that Michelle and Adam Paul Laxalt’s privacy be respected.

Domenici was a key figure in the scandal over the firings in 2006 of nine U.S. attorneys—including David Iglesias in New Mexico—during the second Bush administration. O’Melveny & Myers partner K. Lee Blalack III, named one of The American Lawyer‘s Fab Fifty Young Litigators in 2007, represented Domenici in investigations by the Senate Ethics Committee and special prosecutor Nora Dannehy related to those terminations.

Dannehy, now deputy attorney general of Connecticut, recommended in 2010 that no criminal prosecutions be initiated as a result of her probe, which involved, among other things, interviews of high-profile GOP operatives such as Karl Rove (who was represented by Patton Boggs partner Robert Luskin).

Domenici expressed anger in 2009 at the more than $700,000 in legal fees his campaign committee accrued as a result of the inquiry. In addition to O’Melveny, other firms paid out of his campaign coffers included Akin Gump Strauss Hauer & Feld, Covington & Burling, King & Spalding, McKenna Long & Aldridge, and Wilmer Cutler Pickering Hale and Dorr, according to our previous reports.

Domenici, who practiced law in Albuquerque in the early sixties before beginning more than 40 years of public service, has eight children with his wife Nancy. One of those children, Peter Domenici Jr., founded Albuquerque’s Domenici Law Firm.

Domenici’s revelation about his extramarital affair comes as current U.S. Senator Robert Menendez, a New Jersey Democrat, hired attorneys from McDermott Will & Emery and Perkins Coie to cope with a congressional ethics probe.

The Blog of Legal Times, a sibling publication, reported Thursday that Menendez is being represented by McDermott government strategies practice head Stephen Ryan and Perkins Coie political law practice chair Marc Elias as he seeks to fend off claims that a major Florida donor allegedly flew him to the Dominican Republic to have sex with prostitutes in return for influence with various government agencies. (McDermott and its lawyers have been a top contributor to Menendez’s political campaigns over the years, according to data compiled by the Center for Responsive Politics.)

The BLT also notes that Menendez has hired former Justice Department spokesman Matthew Miller, who once worked for the Garden State senator, to assist him. Miller told Politico this month that he and Menendez have been friends for years and that "like a lot of people, I want to do anything I can to help fight these ridiculous smears."