WASHINGTON--Former top U.S. official John Bolton says that Donald Trump is unique among U.S. presidents for incorporating business concepts--rather than a strategic doctrine--in his foreign policy approach with allies.

Bolton, who served about 18 months as Trump's national security adviser, made that observation during an interview on June 30 in a videoconference with The Asahi Shimbun.

Bolton was asked about the proposal he made to Japanese officials in July 2019 to drastically increase host nation support for the U.S. military from about $2.5 billion (about 270 billion yen) a year to $8 billion (about 850 billion yen).

He wrote about that proposal in his recently published tell-all book “The Room Where it Happened.”

“This was a manifestation of Trump’s approach to alliances, which is based more on the way he does business,” Bolton said.

He added, “For a stable U.S. foreign policy and that of the allies that want to join with it, there has to be an ongoing relationship of trust. This is not an accounting matter.”

The memoir, released on June 23, provides details into foreign policy decisions in the Trump administration, especially between April 2018 when Bolton was named as national security adviser and September 2019, when he was dismissed.

Regarding the July 2019 visit to Japan by Bolton for a meeting with Shotaro Yachi, who then headed the National Security Council secretariat, Bolton wrote that it was Trump’s idea to raise Japan’s host nation support to $8 billion a year.

In the interview, Bolton explained that the figure was “derived from Department of Defense calculations based on a variety of factors” and “an effort to try to assign costs to a lot of factors that had not previously been looked at.”

But Bolton did not provide details about the breakdown of what the United States wanted Japan to pay for.

He explained that proposal was “a manifestation of Trump’s approach to alliances, which is very transactional, based on a monetary relationship, not a political or values-oriented relationship.”

Bolton pointed out that approach was “a fundamental change from the way the United States has regarded its defense alliances in the past.”

Bolton also revealed that rather than consider the alliance with Japan as a mutual relationship, Trump “always liked to say, ‘Well, we’re defending Japan.’"

The current agreement with the United States over host nation support is set to expire at the end of fiscal 2020 and negotiations are expected to intensify in the coming months.

Bolton said the proposal he made in summer 2019 was an “asking price” from the Trump administration and added that the actual figure would likely be lower.

He explained that he brought up the figure because he wanted to demonstrate to his Japanese counterpart that “this particular initiative was the president's alone. The risk of not paying serious attention to it is that the alliance itself could be jeopardized.”

When asked about the possibility of Trump deciding to reduce or withdraw U.S. troops based in Japan if Tokyo did not agree to pay a sharp increase in host nation support, Bolton said, “I don’t think it’s a trivial possibility.”

He also said there was a “real risk” of the United States pulling out of NATO and bilateral alliances, including the one with Japan, if Trump won re-election in November.

Bolton was also critical of Trump’s efforts to pressure allies to pay more for host nation support.

“The desire to have the allies spend more is not only to meet their fair share of the burden, but to make the alliances stronger,” he said. “The overwhelming majority of Americans would reject this transactional approach, where it's just a matter of money, that we're mercenaries.”

Bolton also acknowledged that his differences with Trump over alliance relationships was “one of the reasons I won't be voting for Trump in November.”

He continued criticizing Trump and said, “Every president, every Japanese prime minister takes politics into account in making their decisions: national security, domestic policy. The difference with Trump is that the politics of getting re-elected predominate over every other issue. He doesn’t follow a strategic doctrine, he doesn't really think in policy terms. He thinks in terms of Donald Trump. That’s why I’m worried about what would happen in a second term.”

Additional excerpts of the interview follow:

Question: In your memoir, you wrote that you passed on Trump’s proposal to have Japan pay $8 billion a year in host nation support. What was the basis for coming up with that figure?

Bolton: This is a figure derived from Department of Defense calculations based on a variety of factors. The calculation of the cost will be discussed between Japan and the United States and that will be worked out. I think the main point I was trying to make was that this was a manifestation of Trump’s approach to alliances based on a monetary relationship, not a political or values-oriented relationship.

I think the overwhelming majority of Americans would reject this transactional approach, where ‘it's just a matter of money, that we're mercenaries.’ I wanted to explain how different Trump was from other presidents.

Q: Was the $8 billion figure an official request?

Bolton: Certainly it is the asking price, and there may well be a price below that, that (Trump) would accept.

I certainly tried to stress to take this Trump initiative seriously. The risk of not paying serious attention to it is that the alliance itself could be jeopardized.

Q: Is there the possibility of Trump withdrawing U.S. troops based in Japan, if it does not agree to the proposal?

Bolton: I don’t think it’s a trivial possibility. I think that's the way Trump thinks. It's one of the reasons I won't be voting for Trump in November.

Q: How do you view Trump’s approach?

Bolton: I think for a stable, long-term U.S. foreign policy, there has to be an ongoing relationship of trust. This is not an accounting matter. The desire to have the allies spend more, is not only to meet their fair share of the burden, but to make the alliances stronger. If you turn the alliances simply into accounting mechanisms, you make the alliances weaker.

Q: You also explain in your memoir that Trump asked Prime Minister Shinzo Abe to serve as mediator with Iran. Could you elaborate?

Bolton: I felt badly for Prime Minister Abe that he had gotten involved in it. I think he operated in good faith, and I just felt badly about the way he was treated by the Iranians. It just showed they’re not any more open to negotiations seriously than the North Koreans are.

Q: When Abe told Trump about his efforts to talk with the Iranians, Trump told him that the more important issue was for Japan to buy more U.S. farm products. What was the context of what he said?

Bolton: The context is getting President Trump re-elected in November. The more U.S. farmers are selling to anybody, but including Japan, the greater the prosperity of the farm states, and the greater the possibility that it would enhance his re-election.

Every president takes politics into account in making their decisions: national security, domestic policy. The difference with Trump is that the politics of getting re-elected predominate over every other issue. He doesn’t follow a strategic doctrine, he doesn't really think in policy terms the way we normally mean that. He thinks in terms of Donald Trump. That’s why I’m worried about what would happen in a second term when Trump is freed from any constraint brought on by the possibility of being re-elected.

(This interview was conducted by Wataru Sawamura and Koii Sonoda. Carter Rice contributed to this article.)