As the U.S. and China continue hashing out trade negotiations, a new player has joined the fray: President Donald Trump‘s national security advisor, John Bolton.

A National Security Council official told CNBC that it was only “natural” that Bolton be involved in recalibrating the U.S. trade relationship with China.

“Rebalancing trade and investment relations are an important component of the President’s overall strategic approach to China, and therefore it is natural that the National Security Adviser would play a role in ensuring U.S. economic officials’ ongoing discussions with China are framed within that strategic approach,” the official said.

Bolton’s involvement in trade negotiations signals a broadening scope of authority for the president’s top national security aide, whose views on the U.S.’ shifting relationships with North Korea and Iran were central points of scrutiny when he was appointed in March.

The high-stakes trade talks between the U.S. and China come as the Trump administration prepares for a June summit with North Korean leader Kim Jong Un, a frequent target of Bolton’s criticism over the years. North Korea, likewise, recently criticized Bolton while threatening to pull out of the landmark meeting. China, which is North Korea’s biggest and most important ally, has played a key role in arranging diplomatic connections between the communist dictatorship and the U.S.

The hawkish Bolton has also been outspoken on China trade policy. In a talk-radio interview in March, Bolton said China has for too long “taken advantage of its place in the world” through “the trade arrangements it has with the United States and other countries,” multiple outlets reported.

He added that a revamped trade policy with China “could be a little shock therapy, get their attention, and hopefully it’ll have a good impact.”

Bolton also suggested, in a 2016 op-ed for the Wall Street Journal, that the U.S. should challenge China’s relationship with Taiwan — which China considers to be an official part of its country through the “one China” policy. He even appeared to suggest that military intervention should not be off the table.

Bolton has had rocky history with North Korea. About a month before he was tapped to join the White House team of core advisors to the president, he penned an op-ed for the Journal laying out a case for a pre-emptive attack on North Korea.

Prior to Bolton joining the Trump team, the White House’s “maximum pressure” campaign had been a seen as a catalyst for progress between the two nations.

Kim Jong Un‘s regime made overtures toward thawing relations with the U.S. and South Korea. Kim vowed to destroy its only known missile test site and agreed to landmark talks with South Korean President Moon Jae-In and, separately, a summit with Trump.

But annual military drills between the U.S. and South Korea, which North Korea views as a threat, spurred the regime to abruptly call off the talks with its southern neighbor and potentially cancel Kim’s meeting with Trump.

Worse for the prospect of the Trump-Kim meeting, which is still currently scheduled for June 12 in Singapore, was North Korea’s angry reaction to Bolton’s latest statements on ridding the rogue regime of nuclear weapons.

Bolton said in television interviews on May 13 that the U.S. had the “Libya model” of denuclearization in mind going into talks with North Korea. Libya’s dictator at the time, Muammar Gaddafi, agreed to relinquish his nuclear weapons in exchange for the U.S. relaxing sanctions on his country.

Gaddafi was later killed in the street by a mob of his own people in a violent insurrection — a vision that appears to serve as Kim’s main takeaway from the “Libya model.”

North Korea’s vice foreign minister on Wednesday said his country does “not hide our feeling of repugnance towards” Bolton, and referenced his remarks about Libya in a searing statement.

Trump quickly distanced himself from Bolton’s analogy in Oval Office remarks last week.

“The Libyan model isn’t a model that we have at all,” Trump said Thursday.