WASHINGTON >> This month, a network of pro-Russian websites began a campaign aimed at undermining confidence in the U.S. defense industry, according to disinformation analysts.

The F-35 fighter jet was one target. The effort, coordinated by a Russian group known as Portal Kombat, spread rumors that U.S. allies purchasing the warplanes would not have complete control over them, the analysts said.

In the past, U.S. cybersecurity agencies would counter such campaigns by calling them out to raise public awareness. The FBI would warn social media companies of inauthentic accounts so they could be removed. And, at times, U.S. Cyber Command would try to take Russian troll farms that create disinformation offline, at least temporarily.

But President Donald Trump has fired Gen. Timothy D. Haugh, a four-star general with years of experience countering Russian online propaganda, from his posts leading U.S. Cyber Command and the National Security Agency.

The FBI has shut down its foreign influence task force. The Cybersecurity and Infrastructure Security Agency has ended its efforts to expose disinformation. And this week the State Department put employees who tracked global disinformation on leave, shutting down the effort that had publicized the spread of Chinese and Russian propaganda. Almost three months into Trump’s second term, the guardrails intended to prevent national security missteps have come down as the new team races to anticipate and amplify the wishes of an unpredictable president. The result has been a diminished role for national security expertise, even in the most consequential foreign policy decisions.

Trump administration officials said that is by design. In Trump’s first administration, some members of his team tried to stop him from executing parts of his agenda, such as his desire to pull U.S. troops out of Syria and Afghanistan, or to deploy them against protesters in American cities.

The president does not intend to allow anyone to rein him in this time.

But tearing down guardrails has created room for America’s adversaries to operate more freely in the disinformation space, according to Western officials and private cybersecurity experts.

This is not how the U.S. national security apparatus is supposed to work, national security experts and former officials say.

The National Security Act of 1947 established the National Security Council to ensure that the president received the most expert advice on an array of global issues. The act also led to the establishment of the Joint Chiefs of Staff, which advises the president on military strategy and planning.

But instead of advice, Trump is getting obedience.

“Right now, the NSC is at the absolute nadir of its influence in modern times,” said David Rothkopf, the author of “Running the World: The Inside Story of the National Security Council and the Architects of American Power.”

Trump is skeptical of NATO, so the Pentagon is considering plans to hand over U.S. command of NATO troops. The president is close to tech billionaire Elon Musk, so the Pentagon invited him to view plans in the event of a war with China in the Pentagon “tank,” a meeting space reserved for secure classified meetings (the White House stopped Musk from getting the China briefing).

Trump fired the director of the National Security Agency and six National Security Council officials on the advice of Laura Loomer, a far-right activist. Michael Waltz, the national security adviser, appeared to have little influence over the dismissals.

“When somebody with no knowledge can come in and level accusations at the NSC senior directors, and Waltz can’t defend them, what does that say?” asked John Bolton, one of those who had Waltz’s job in Trump’s first term.

Back then, Bolton said in an interview, Trump made clear that he disliked pushback, once saying: “I knew I should have made Keith Kellogg the national security adviser. He never tells me his opinion unless I want it.”

Kellogg, a retired lieutenant general, is now Trump’s adviser to Ukraine.

In February, Kellogg had cautioned against an Oval Office meeting between Trump and President Volodymyr Zelenskyy of Ukraine because he was worried such plans were premature, two administration officials said.

The meeting took place anyway, and blew up. Trump temporarily cut off crucial aid and intelligence sharing to Ukraine, complaining that Zelenskyy had not sufficiently expressed his gratitude.

The rest of the national security team cheered the president.

“Amen, Mr. President,” Defense Secretary Pete Hegseth wrote on social media, applauding Trump’s stance.

Zelenskyy “should apologize for wasting our time for a meeting that was going to end the way it did,” Secretary of State Marco Rubio added during a CNN appearance.

Despite his role, Kellogg has been eclipsed in negotiating an end to the war between Russia and Ukraine by Steve Witkoff, a real estate developer who was initially tapped to be the special envoy for the Middle East. During Trump’s first term, senior members of his national security team became a sort of guardrail against the mercurial instincts of a president often disdainful of anything he sees as reflecting the national security establishment’s policy preferences.

His first defense secretary, Jim Mattis, talked him out of using torture as a tool for interrogating detainees. Mattis and Bolton talked him out of withdrawing from NATO. His second chair of the Joint Chiefs of Staff, Mark Milley, and his second defense secretary, Mark Esper, talked him out of using active-duty troops to shoot Black Lives Matter protesters in the legs, as the president had suggested.

Sean Parnell, the Pentagon press secretary, did not respond to requests for comment. Brian Hughes, the NSC spokesperson, said in a statement that “members of the national security team of the first term actively attempted to undermine President Trump including General Milley calling his then-Chinese counterpart behind the president’s back.”

Hughes added that it was the job of Trump’s team to “carry out the elected commander in chief’s agenda, not weaken it.”