United States President-elect Donald Trump's return to the White House next year signals the possibility that parts of the South Korea-US alliance or regional security-related matters could be negotiated away.

South Korea must brace for any attempt by Trump to do so, even when dealing with nuclear-armed North Korea and its leader, Kim Jong-un, said Chung Duck-koo, founder and chair of Seoul-based think tank North East Asia Research Foundation, on Wednesday.

"The Korea-US alliance is never a tradable asset," Chung said in a keynote speech at the inaugural Korea Herald Security Forum 2024, titled "Alliance after US Election 2024: A Seoul Perspective" held at the National Assembly Museum in Seoul.

"The Korea-US alliance is not a bargaining chip. North Korea will try to use President Trump as the target of negotiations based on brinkmanship, and will start performing more dangerous stunts to achieve its goal," he also said.

The 76-year-old, who was formerly an industry minister and a lawmaker in the National Assembly, also cautioned that there would be no going back once the security is bargained away.

"If Washington gives up on its pursuit of a complete, verifiable and irreversible denuclearization of North Korea, and instead moves on to negotiate with North Korea over arms control, Washington would be making a serious mistake -- the same mistake it had made when it declared the Acheson line," Chung said, referring to a 1950 declaration by the then-US secretary of state Dean Acheson, which was blamed for encouraging North Korea's invasion of South Korea to start the Korean War.

Regardless of Trump's approach to North Korea, South Korea should brace for whatever situation.

"The South Korea-US alliance has expanded from the 'ironclad' security alliance based on shared values to the economic security in the Joe Biden administration. Now, with the advent of the second term of the Donald Trump administration, there comes a time when every layer of security ties could become a tradable asset," Chung said.

He added South Korea could not overcome any challenges posed by the Trump administration through a conventional value-based approach, given the unpredictable nature of Trump, and his transactional approach to diplomacy.

"In the next four years of the Trump administration, we should get used to seeing every diplomatic element as part of a transactional diplomacy," Chung said.

One of the ways to overcome the obstacles, from South Korea's standpoint, is to let its US counterparts recognize that the US military bases -- including in Pyeongtaek and Osan in Gyeonggi Province, as well as Gunsan, North Jeolla Province -- have already served as the closest outposts for the US to keep superpowers like China and Russia in check.

South Korea's geographically strategic location proves that the matter of US Forces Korea-related cannot be easily negotiated.

"Money can't buy regional security. It's like money can't buy freedom," Chung said.

The US must recognize that these outposts will play an extremely important role in its national strategy, he added.

"Money can't buy strategic assets. How can a single country offer (land for) such enormous military posts of the US? These posts affirm that South Korea geographically lies in the front line of the US' northeast Asia strategy."

Chung also called on South Korea to go beyond the Washington Declaration in 2023 when it comes to strengthening trilateral ties of South Korea, the US and Japan to counter North Korea, given the gravity of concerns about North Korea's nuclear weapon development and strengthening military collusion with Russia.

"Seoul needs to honestly share with our US counterparts over whether Seoul is really capable of exercising deterrence against North Korea's nuclear weapons with US strategic weapons," Chung said.

"I see the expert consensus on the argument that we've already reached a level at which we shall fight North Korea's traditional weapons with our own traditional weapons."

He also said it is high time for South Korea to keep in mind that vigilance is key to survival.

"In the coming days, South Korea should strengthen its role as a supplier of essential goods to all trade partners," he said.

South Korea and the US should be "sailing in the same boat with a shared dream, a trust asset, complementarity in science, technology and industry and balanced national interests," he also said.