The Atlantic’s Jeffrey Goldberg got added to the White House Signal group chat because, months earlier, Waltz's Apple phone contact update algorithm scraped up Goldberg’s number from an Oct 2024 pre-election Goldberg email that had been copied and pasted into a text from then-Trump campaign spokesperson Brian Hughes to Waltz - and incorrectly suggested to Waltz to add the contact-algorithm-scraped-up Goldberg contact as that of text sender (then-Trump spokesman's Brian Hughes') contact info.
Article:
"Donald Trump’s national security adviser Mike Waltz included a journalist in the Signal group chat about plans for US strikes in Yemen after he mistakenly saved his number months before under the contact of someone else he intended to add, according to three people briefed on the matter.
"The mistake was one of several missteps that came to light in the White House’s internal investigation, which showed a series of compounding slips that started during the 2024 campaign and went unnoticed until Waltz created the group chat last month.
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"The disclosures nonetheless triggered a “forensic review” by the White House information technology office, which found that Waltz’s phone had saved Goldberg’s number as part of an unlikely series of events that started when Goldberg emailed the Trump campaign last October.
"According to three people briefed on the internal investigation, Goldberg had emailed the campaign about a story that criticized Trump for his attitude towards wounded service members. To push back against the story, the campaign enlisted the help of Waltz, their national security surrogate.
"Goldberg’s email was forwarded to then Trump spokesperson Brian Hughes, who then copied and pasted the content of the email – including the signature block with Goldberg’s phone number – into a text message that he sent to Waltz,so that he could be briefed on the forthcoming story.
"Waltzdid not ultimately call Goldberg, the people said, but in an extraordinary twist,inadvertently ended up saving Goldberg’s number in his iPhone – under the contact card for Hughes, now the spokesperson for the national security council.
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"According to the White House,the number was erroneously saved during a “contact suggestion update” by Waltz’s iPhone, which one person described as the function where an iPhone algorithm adds a previously unknown number to an existing contact that it detects may be related.
"The mistake went unnoticed until last month when Waltz sought to add Hughes to the Signal group chat – but ended up adding Goldberg’s number to the 13 March message chain named “Houthi PC small group”, where several top US officials discussed plans for strikes against the Houthis.
"Waltz said in the immediate aftermath of the incident that he had never met or communicated with Goldberg. He also suggested on Fox News that Goldberg’snumber had been “sucked” into his phone,seemingly in reference to how his iPhone had saved Goldberg’s number."
https://www.theguardian.com/us-news/2025/apr/06/signal-group-chat-leak-how-it-happened