Former US National Security Advisor John Bolton warned in a new edition of his memoir Tuesday that former President Donald Trump, if reelected, could attempt to reach a "reckless" deal on North Korea's nuclear program that would alienate South Korea.

Bolton, who served as national security advisor under Trump from 2018-2019, made the prediction in the new foreword of his book, "The Room Where It Happened," as Trump is expected to face President Joe Biden in the Nov. 5 presidential election.

"Imagine Trump's euphoria at resuming contact with North Korea's Kim Jong-un, about whom he famously boasted, 'We fell in love,'" he wrote in the 18-page foreword that entails his forecast for what would happen under a potential second-term Trump administration.

"Trump previously almost gave away the store to Pyongyang, and he could try again early in a second term. A reckless deal on the North's nuclear weapons program would further alienate Japan and South Korea, and extend China's influence," he added.

Bolton also forecast that burgeoning military cooperation between Pyongyang and Moscow would not keep Trump from reuniting with the North Korean leader.

"Pyongyang's emerging role in the Beijing-Moscow axis, including providing ammunition and weapons for Russia to use against Ukraine, will not deter Trump from getting back together with Kim," he claimed.

With Trump having a commanding lead in the Republican nomination race, attention has been gravitating to what policy changes Trump would bring about should he return to the White House.

Trump is known for his leader-to-leader diplomacy with the North, which led to three face-to-face meetings with Kim, though serious negotiations between the two sides stalled following the no-deal summit in Hanoi in 2019.

In the foreword, Bolton also predicted that Taiwan and others along China's Indo-Pacific periphery could face "real peril" in a second Trump term.

"He still shows no recognition of Taiwan's importance, as he earlier ignored Beijing's crushing of Hong Kong's autonomy. The near-term risks of China's manufacturing a crisis over Taiwan will rise dramatically," he said.

He went on to say that it is unlikely Beijing will "physically" invade Taiwan since crossing the Taiwan Strait's open ocean is a "formidable" task. "More likely, China's Navy will blockade the island, and perhaps seize Taiwanese islands near the mainland, just to show that it can," he said.

Bolton also expressed concerns that Trump may believe the "one-China" policy means the US can accept Beijing's absorbing of Taiwan.

"But our Indo-Pacific allies would be justifiably appalled," he said. "The loss of Taiwan's independence, which would soon follow a US failure to resist Beijing's blockade, could persuade most countries near China to follow a 'Finlandization' policy at best."

Finlandization refers to a process by which a powerful nation makes a smaller neighbor refrain from opposing the former's external policy while allowing the latter to keep its independence and political system. (Yonhap)