His support comes amid calls for the national security adviser to step down, with one official calling him a 'f***ing idiot.' Waltz started the text chain to discuss the plans to bomb the Houthis in Yemen and added The Atlantic magazine's editor-in-chief Jeffrey Goldberg.

'Everyone in the White House can agree on one thing: Mike Waltz is a f***ing idiot,' the source, identified as a 'person close to the White House', bluntly told Politico.

Trump, however, told NBC News: 'Michael Waltz has learned a lesson, and he's a good man.' 

He blamed staff for the mixup. 

When asked what he was told about how Goldberg came to be added to the Signal chat, Trump said, 'It was one of Michael's people on the phone. A staffer had his number on there.' 

In the Signal app group, entitled 'Houthi PC small group,' Goldberg was privy to conversations between Waltz, Defense Secretary Pete Hegseth, Vice President JD Vance and other top administration officials.

He wrote about how operational details were discussed and claimed Hegseth shared sensitive information that could be damaging to the country if it fell in the wrong hands.

The story blew up the internet when it was posted on Monday. Several critics asked why the administration was discussing sensitive material on an app instead of government systems designed to communicate classified data. 

Trump dismissed the story as a non-issue, saying that Goldberg's presence on the chat had 'no impact at all.' The attacks, he said, were 'perfectly successful.'

He also said he wasn't worried about the amount of attention the story received, saying it was 'the only glitch in two months, and it turned out not to be a serious one.'

Goldberg was critical of Waltz for adding him to the conversation and using the app to communicate. It's unclear who Waltz meant to include.

'I'm thinking to myself, I'm glad Mike Waltz didn't invite a Houthi into the group or a Russian spy, or an adversary of the United States,' Goldberg told MSNBC.