California is losing another storied Democratic lawmaker honed by decades in the trenches with the announcement Thursday by Rep. Henry Waxman, 74, of Los Angeles that he will retire at the end of his term.

Waxman’s announcement follows that of fellow veteran Rep. George Miller of Martinez two weeks ago.

Waxman’s departure will only intensify speculation about House Minority Leader Nancy Pelosi’s future. Her spokesman Drew Hammill reminds us that she has already announced that she will run for re-election in her San Francisco district. Pelosi is losing two of her most effective and trusted lieutenants, but there are other Californians in her inner circle: Anna Eshoo of Palo Alto and Mike Thompson of St. Helena are trusted allies. A new generation of smart young California Democrats is also making its mark, including Jared Huffman of San Rafael and Eric Swalwell of Dublin.

As one Democratic aide told us, anyone who tries to speculate about Pelosi’s future is on a fool’s errand. This aide called the Miller and Waxman retirements a “generational shift” that is “hard for people to adjust to” because both lawmakers have “always been there” to anyone middle aged or younger. The aide reminded us that Waxman and Miller were both heralds of an earlier shift that unseated then-dominant Southern Democrats, powerful committee chairmen, dethroned by the then young California liberals.

“I am grateful for the friendship of my colleagues in Congress on both sides of the aisle,” Waxman said in his announcement. “And I am honored that I served under the leadership of my friend, Nancy Pelosi, the first female leader and speaker of the House.”

But with odds of Democrats recapturing the House majority close to vanishing, and Tea Party anti-government forces frustrating lawmakers on both sides, staying in the chamber to fight another day is losing its luster for some longtime liberals.

Like Miller, Waxman was first elected during the Watergate era. He became one of the most formidable lawmakers in Washington, deftly skewering the chieftains of the tobacco industry during hearings in 1994. He and Miller were among the crafters of the Affordable Care Act, which was as much the product of Pelosi’s relentless efforts as President Obama’s. Waxman said the law’s enactment was the realization of one of his “lifelong dreams.”

Waxman has expressed frustration with the lack of serious lawmaking in the House over the past two years, complaining to this reporter during the government shutdown last year of the circus-like atmosphere on the Hill.

Waxman has seen his share of defeats, notably a giant cap-and-trade bill during Obama’s first term that would have reduced carbon emissions. The bill narrowly passed the House but was killed in the Senate, and opposition in coal country and the industrial heartland was one of several factors that led to Pelosi’s loss of the gavel in 2010.

Waxman said the Environmental Protection Agency’s plans to cut emissions from coal-fired plants will help achieve the same goal.

He is especially proud of amendments to the Clean Air Act that he helped push through in 1990. “It took a decade of effort,” he said, “but the controls on urban smog, toxic air pollution, acid rain and ozone-depleting chemicals have saved lives and vastly improved our air quality.”

Waxman was the first lawmaker 20 years ago to attempt to force the Food and Drug Administration to restrict the use of antibiotics in livestock, which the Centers for Disease Control and Prevention now says is a threat to human health. The FDA only recently issued a rule calling for voluntary withdrawals of antibiotics to fatten livestock, but they are still allowed at low doses to prevent diseases in animals living in concentrated feedlots.

Here’s Waxman on why he’s leaving Congress:

“There are elements of Congress today that I do not like. I abhor the extremism of the Tea Party Republicans. I am embarrassed that the greatest legislative body in the world too often operates in a partisan intellectual vacuum, denying science, refusing to listen to experts, and ignoring facts.

“But I am not leaving out of frustration with Congress. Even in today’s environment, there are opportunities to make real progress. Last Congress, I worked with Democrats and Republicans in the House and Senate to pass legislation that will ease the nation’s growing spectrum shortage, spur innovation in new ‘Super WiFi’ technologies, and create a national broadband network for first responders. Just last year, I worked on a bipartisan basis to enact legislation strengthening FDA’s authority to stop dangerous drug compounding and to track pharmaceuticals through the supply chain.

“And I am not leaving because I think House Democrats have no chance to retake the House. House Republicans have no compelling vision for the future. The public understands this, and I am confident that the Democrats can regain control of the House.

“The reason for my decision is simple. After 40 years in Congress, it’s time for someone else to have the chance to make his or her mark, ideally someone who is young enough to make the long-term commitment that’s required for real legislative success. I still feel youthful and energetic, but I recognize if I want to experience a life outside of Congress, I need to start soon. Public office is not the only way to serve, and I want to explore other avenues while I still can.”

“I have had a long career and an eventful one – and I wouldn’t trade any of it. I woke each day looking forward to opportunities to make our country stronger, healthier, and fairer. And I will always be grateful for this honor and privilege.”