John Bolton’s former chief of staff urged him to reconsider releasing his forthcoming tell-all book about his experience as President Trump’s national security adviser, calling it a “dangerous precedent” that could dissuade future presidents from seeking advice on national security matters.

“Given the importance of protecting a president’s confidential discussions with his senior advisers, I strongly disagree with Bolton’s decision to release the book before the November presidential election and call on him to withdraw it from the publisher immediately,” Fred Fleitz wrote in an opinion piece for Fox News on Monday.

“Presidents must be able to candidly consult with their advisers without worrying they will leak these discussions to the press or obtain high-dollar book contracts to publish them. A book by a former national security adviser ahead of a president’s reelection bid may set a dangerous precedent since it could discourage future presidents from seeking advice from expert advisers on sensitive national security matters,” he argued.

The book, The Room Where it Happened, is set to be published on March 17.

Bolton made at least one bombshell claim in the book, alleging that Trump conditioned aid to Ukraine on the country investigating Joe Biden, the former vice president and a top contender for the 2020 Democratic presidential nomination. The revelation undermines the Trump defense team's claim that the freeze on security assistance to Ukraine was separate from the president pressing Kyiv to announce investigations into his political rival.

Fleitz, who was Bolton’s chief of staff at the State Department from 2001 to 2005 and again at the National Security Council in 2018, said his former boss made an “inexplicable” misstep in sending the manuscript to the National Security Council to review during Trump’s impeachment trial.

“Under such circumstances, a leak of the manuscript was all but certain,” he wrote, referring to the New York Times report on the matter.

Fleitz continued: “If a manuscript of this sensitivity was to be published at all, this should happen after the election, not in the spring of 2020. I don’t understand the need for a former National Security Adviser to publish a tell-all book critical of a president he served, especially during a presidential reelection campaign that will determine the fate of the country. There will be a time for Bolton to speak out without appearing to try to tip a presidential election.”

[Read more: ‘Only to sell a book’: Trump denies Bolton claim that Ukraine aid was tied to Biden investigation]