Exclusive: One-third of top U.S. cyber force has left since Trump took office

The big picture: Trump officials are actively pursuing plans to increase offensive cyber operations against adversarial nations like China — and experts warn those nations are bound to respond in-kind to those strikes.

• But security experts fear that with a smaller cyber defense agency, the country won't have the resources needed to protect the homeland.

Driving the news: The White House suggested cutting CISA's workforce by 1,083 positions — from 3,732 employees to 2,649 roles — during the 2026 fiscal year in its proposed budget, released Friday.

• However, the agency has already reached those numbers, sources tell Axios.

Zoom in: About 600 people at CISA took the Department of Homeland Security's second buyout offer in the last two months, according to a source familiar with the matter. Their last day was Friday.

• Roughly 174 people had taken the first round of deferred-resignation offers as of March 28, according to a second source familiar with the matter.
• The rest of the roughly 1,000 departures likely involved people working on government contracts or teams — like the election integrity unit or diversity-and-inclusion offices — that have reportedly been cut, the former official told Axios.

Between the lines: Sources did not have precise details on which departments have been slashed, but public social media posts and other reporting suggest the losses are widespread — including in several of CISA's most visible and impactful initiatives.

• An internal memo sent to employees last week says that virtually all of CISA's senior officials have now left.
• Lauren Zabierek and Bob Lord, two officials who oversaw the agency's touchstone "Secure by Design" initiative, left last month.
• Matt Hartman, the No. 2 official in CISA's cybersecurity division, departed last week.
• Members of CISA's international partnerships and engagement division also left, according to LinkedIn.
• Lisa Einstein, who was CISA's chief AI officer, resigned in February.
• Boyden Rohner, assistant director of CISA's integrated operations division, took an early retirement offer in April.

What they're saying: "I've personally seen how CISA has lost its very best," Jack Cable, CEO and co-founder of Corridor and a former CISA employee who departed in January, told lawmakers during a field hearing in Silicon Valley last week.

• "In the face of increasing threats, we can't undermine the capacity of America's cyber defense agency and its ability to attract and retain the best technical talent," he added. "This only makes us less secure as a nation."

In a statement to Axios, CISA executive director Bridget Bean said the agency has "the right team in place to fulfill that mission and ensure that we are prepared for a range of cyber threats from our adversaries."

• "CISA is doubling down and fulfilling its statutory mission to secure the nation's critical infrastructure and strengthen our collective cyber defense," Bean said.

The intrigue: The agency has considered scrapping plans for mass layoffs due to the overwhelming response to the buyouts, the former official noted.

• Politico Pro previously reported on this possibility.

What to watch: Sean Plankey, Trump's pick to run CISA, will testify before the Senate Homeland Security Committee on Thursday and is expected to field questions about the workforce cuts.

• CISA has already started to appoint new officials to senior roles: Madhu Gottumukkala, former CIO at South Dakota's Bureau of Information and Technology, is now the agency's deputy director. Kate DiEmidio, who most recently was the vice president of government affairs at Dragos, just came on board as CISA's legislative affairs chief.

Go deeper: Government contractors are lining up to work with DOGE