Since the White House’s first term, sharing favorite topics in ally President Donald Trump has been a favorite topic for the U.S. president.

But as more countries try to evade a deal in their second term to evade the ghost of tariffs, Trump is making his own move: bundle negotiations about trade, tariffs and defense cost sharing into a comprehensive deal, which he calls “one-stop shopping.”

There is one such country in South Korea that is South Korea, with about 28,500 US troops South Korea. On April 8, Trump wrote in The Society of Truth that he discussed “the payments for the large military protection we provide to South Korea” and then-President Han Duck-soo.

"We are proposing other topics that are not covered by trade and tariffs and are negotiating at the same time. "One-stop shopping" is a beautiful and efficient process!!!" Trump wrote.

South Korean officials reportedly said defense payments were not on the table, but two presidential candidates in the country, Lee Jae-Myung and Kim Moon-Soo, said they were willing to discuss a defense cost-sharing agreement.

However, analysts told CNBC that the trading method is not necessarily good for the United States.

At the Munich Security Conference in February, then-Minyapaal Defense Minister Ng Eng said: "Trade and security are said to be two aspects of the same coin, and people assume that as the trade dependence changes, security alliances will follow."

But the image of the United States in Asia says: “has gone from liberator to huge disruptors to landlords seeking rent.”

Bruce Bennett, a professor of policy analysis at the Rand School of Public Policy, told CNBC that the U.S. president may raise defense payments in trade negotiations.

"This is how he does business," Bennett said. "So, it's not that he absolutely wants to bring troops home, but that he wants to recognize and accept the responsibilities of our allies," he said.,,,,,“He added.

This is a position put forward by US Secretary of Defense Elbridge Colby, who said in a 2024 interview that US military in South Korea should be overhauled to make it more "related" to deal with China, not North Korea.

One way South Korea can "pay more" is to invest in its troops and buy more U.S. military equipment, Bennett said.

He added that this will allow the South Korean military to bridge any capacity gap while making the U.S. military more focused on China.

“(If) the South Korean government says we are voluntarily … increasing the budget by $3 to $4 billion, we will use it to buy equipment so the United States can shift focus, and I think that will go a long way toward meeting the president’s interests.”

South Korea uses 2.6% of its GDP to national defense in 2024, exceeding the global average of 2.5%, and one of the highest averages in the world, according to the Stockholm International Peace Research Institute.

In 2025, the country allocated 612.25 trillion South Korean champions ($43.83 billion) to its defense, or 3.1% increase from the previous year.

But this trading approach will damage the credibility of the United States, said Hossick Nan, an assistant professor in the Department of Sociology and Political Science at Jacksonville State University.

NAM added that using the deployment of U.S. forces as a leverage for trade negotiations could lead close allies to see the U.S. commitments not very credible.

“In the long run, this position could restructure the United States into an isolated superpower.”

South Korea does not need to make any financial contribution in its initial agreement in 1966 with the U.S. troops stationed in the country, known as the status of the Force Agreement.

The cost share became a feature of the alliance only in 1991, when Seoul agreed to share the burden of stationing U.S. troops in three regions, namely logistics, local labor and military construction.

Nan explained that South Korea's rapid economic growth since the 1960s created conditions for cost distribution.

"The two countries also agree that their relationship should go beyond simple aider and receptor dynamics," he noted.

The funds provided by the South Government also created local jobs and helped local industries.

"With the construction, most projects are conducted by Korean construction companies. In terms of logistics, equipment, services and facilities, they are provided by Korean companies."

In October 2024, Seoul agreed to increase its contribution to the U.S. military to 8.3% to 1.52 trillion won (USD 1.13 billion) in 2026.

But given the 2024 agreement covers the 2026-2030 period, Trump's "one-stop shopping" stance with the defense agreement bundling trade with the defense agreement could put the Biden administration's latest cost-sharing agreement at risk.