It’s already widely known that Donald Trump is not fond of note-taking. “What about these notes?” the president once fumed at then-White House counsel Don McGahn, according to Robert Mueller’s report. “Why do you take notes? Lawyers don’t take notes, I never had a lawyer who took notes.” In a separate meeting, described in a forthcoming book by an anonymous senior administration official, the president flew off the handle at another aide he noticed scribbling in a notebook: “What the [expletive] are you doing?” Trump said, according to an excerpt published in the Washington Post last week. “Are you [expletive] taking notes?” Despite the onslaught, those around the president have bravely continued to put pen to paper. And apparently, the White House is once again on edge thanks to a dutiful note-taker.

Sources close to Trump told Axios Sunday that they are concerned about potential notes John Bolton might share with House lawmakers leading an impeachment inquiry into the president. The ousted national security adviser, who is said to have vehemently opposed Trump’s efforts to extort Ukraine into conducting politically-motivated investigations, was apparently one of the “most prolific” note-takers in the White House—and, his lawyer said, he was present for several key meetings related to the Ukraine scandal. That has raised concerns among Trump aides that Bolton has more information than any witness who’s testified so far. “Bolton was a voracious note-taker, in every meeting,” one aide told the outlet.

Bolton’s habit could prove troublesome for Trump, who, along with Rudy Giuliani, pressured incoming Ukrainian President Volodymyr Zelensky to investigate potential 2020 foe Joe Biden and a conspiracy theory about the 2016 election. The erstwhile national security adviser was apparently no fan of the effort; former aide Fiona Hill told House investigators last month that he’d described Giuliani as a “hand grenade” and wanted it known that he was “not part of whatever drug deal [Gordon Sondland] and [Mick Mulvaney] are cooking up” with Trump’s lawyer. Bolton won’t testify without a court ruling, his lawyer wrote last week, but appears open to doing so and has teased new information relevant to the Democrat-led probe. Bolton was “personally involved in many of the events, meetings, and conversations about which you have already received testimony, as well as many relevant meetings and conversations that have not yet been discussed in the testimonies thus far,” his counsel, Charles J. Cooper, wrote.

A senior administration official cautioned Bolton against revealing the potential undisclosed information, warning that concealing his notes and not submitting them for review upon his exit “could lead to legal repercussions depending on the contents,” according to Axios. But it’s not clear that Bolton’s disclosures would violate any rules, and the threat mostly seems to underscore the fear around Bolton’s testimony in the White House. It remains to be seen whether Bolton, who was given walking papers in September, will in fact testify, and what he’ll say if he does. But it probably won’t do much to change Trump’s mind on note-takers in his ranks.

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