When the most famous ex-CIA spy alive is concerned about the world blowing up, there’s probably something worrisome in that.

Sure, this is the kind of fretting Valerie Plame Wilson has been doing since her cover was famously blown in 2003 by an operative of President George W. Bush’s administration. But as she dashed through San Francisco last week to speak at a cyberterrorism conference, Plame said she sees the country heading into a dangerously unstable period that just might result in disaster involving her No. 1 concern of the past several years:

Nuclear bombs.

Blame it on President Trump, his reckless ways, and the “low-quality people he surrounds himself with,” she said.

“What I find most concerning about him is his access to the nuclear command and control structure,” Plame said the other day over breakfast at a diner before delivering a speech to the RSA 2017 Conference on international security. “We’re still deciding whether to take Trump literally or seriously. But during the campaign he made comments about ‘So what if Japan gets a nuclear weapon,’ and intimating that a nuclear strike is not out of the question.

“He is so casual and reckless. Impulsive, to say the least. This is a man who gets riled up by a tweet. Is this the guy you want to make nuclear decisions?”

Plame, 53, was an undercover CIA operative whose specialty was weapons of mass destruction, and she says her illegal unmasking in 2003 shook her life to the core — but not her determination to fight nuclear proliferation as one of the greatest threats to humankind. She was outed in retaliation by White House officials for her husband, ex-Ambassador Joseph Wilson IV, disputing the Bush administration’s justifications for invading Iraq. When the couple moved to New Mexico in 2006, Plame turned her attentions to more civilian pursuits.

Her career as a spy may have ended with her public unveiling, but the exposure from the investigations and fame through her book on the scandal, “Fair Game” — turned into a movie starring Naomi Watts and Sean Penn — have given her visibility she would never otherwise have had. She puts that to purposeful use for a bevy of organizations whose boards she sits on, including the Ploughshares Fund and Global Zero, which both combat nuclear proliferation.

She’s also on the board of Global Data Security, a cybersecurity company — she also specialized in that in the CIA — which led her to last week’s conference in San Francisco.

And even though she’s not in the spy business anymore, she still has plenty of friends in the national intelligence community. She says they are as troubled by Trump as she is, with one of the greatest offenses being his postinauguration speech at the CIA in front of a wall honoring slain operatives.

“He stood in front of that wall that has the stars for those who have fallen, and he used it as a campaign rally,” she said. “I know two of the people whose stars are up there. What he did — it feels demeaning, it feels sullied, it feels wretched.

“And only a few weeks prior to that, he had been so derogatory in his comments about the intelligence community, calling them Nazis. There is real apprehension. It’s not starting off in a very positive vein.”

Plame said that, as a specialist in keeping security tight, she has been particularly mortified by Trump’s apparent sloppiness — from neglecting to go to a secure location at his Mar-a-Lago estate when he received information about a North Korean missile launch to one of Trump’s supporters cavalierly posting a Facebook picture of himself at a Trump event with “Rick,” the military officer carrying the president’s “football” of nuclear attack codes.

However, watching Trump’s news conference Thursday made her even more concerned as he casually mused that he could shoot a Russian ship “right out of the water,” and that “nuclear holocaust would be like no other.”

“So, this is the president to whom we have entrusted our nuclear codes?” she said. “The incompetence we’ve seen is — and I know this is a widely overused word right now — unprecedented. And it’s more than just Trump.

“The fact that Steve Bannon is on the National Security Council is horrifying. And what’s happened with Michael Flynn is fascinating — he is dangerous.”

Flynn resigned last week as Trump’s national security adviser after revelations that he misled Vice President Mike Pence about his contacts with a Russian official. Bannon is chief strategist to the president and formerly ran Breitbart News, a fringe-right website specializing in conspiracy theories.

“The only silver lining in all this may be that after two decades of people saying, ‘Oh, didn’t the Cold War end, aren’t nuclear weapons a thing of the past?,’ maybe they’ll go, ‘Hey, wait a minute,’” Plame said. “It’s actually a more dangerous world than ever now, and what we have in the White House is the gang that couldn’t shoot straight.

“Maybe this will wake people up.”

Kevin Fagan is a San Francisco Chronicle staff writer. Email: kfagan@sfchronicle.com Twitter: @KevinChron