Hillary Clinton on Friday called the Trump administration’s approach to governing both dumb and dangerous in an essay excoriating the Signal chat scandal and the Elon Musk-led mission to slash the federal workforce, and concluding that Trump would make the US “feeble and friendless”.

The former secretary of state and Democratic presidential candidate wrote an op-ed for the New York Times that has been given the headline: “How much dumber will this get?” and opens: “It’s not the hypocrisy that bothers me; it’s the stupidity.”

Clinton starts with the Signal chat group scandal, when Donald Trump’s national security adviser, Mike Waltz, mistakenly added a top US journalist to a small group of government leaders on the encrypted but unclassified app and then the defense secretary, Pete Hegseth, proceeded to discuss intricate details of a forthcoming airstrike on Houthi militants in Yemen and report back to the group on the deadly results.

The US vice-president, JD Vance, was included, who took another swipe at European reliance on US military security, and so was the director of national intelligence, Tulsi Gabbard. Hegseth relayed times that US fighter jets would take off and his updates on death and destruction on the ground elicited triumphant comments and emojis from some others in the group.

Clinton wrote: “Top Trump administration officials put our troops in jeopardy by sharing military plans on a commercial messaging app and unwittingly invited a journalist into the chat. That’s dangerous. And it’s just dumb.”