Korean and U.S. troops participate in a joint river-crossing drill at a training ground in the border county of Yeoncheon, Gyeonggi Province, March 20. Yonhap

An early start to defense cost sharing negotiations between Korea and the United States is unlikely to fully mitigate the so-called "Trump risk," analysts said, as the allies are set to begin their first round of talks to determine how much Korea should contribute to the cost of stationing American soldiers here from 2026.

The Special Measures Agreement (SMA) negotiations, which outline Seoul's financial obligations for stationing 28,500 U.S. Forces Korea (USFK) troops, are scheduled to kick off in Honolulu, Hawaii, Tuesday (local time) and will run through Thursday, according to Korea's Ministry of Foreign Affairs.

The discussions, led by Korea's chief negotiator, Lee Tae-woo, and his U.S. counterpart, Linda Specht, involve foreign, defense and economic officials from the two sides.

The negotiations will determine costs starting from 2026, with the current six-year SMA set to expire at the end of 2025. The early start, with one year and eight months remaining until expiration, deviates from the previous timeline of typically beginning talks one year before expiration.

Yang Uk, a defense analyst at the Asan Institute of Policy Studies, believes that the possibility of former U.S. President Donald Trump's return to the White House led the allies to initiate negotiations earlier than usual.

However, he was skeptical about whether Korea will achieve its desired outcome.

"I think it's not a bad move for Korea to launch the discussions early. But beginning talks on an earlier timeframe does not guarantee that it will be able to achieve its goal of reaching an agreement early to prevent Trump, if reelected, from making radical demands for increased funding," Yang told The Korea Times.

"From Korea's perspective, negotiating with the Joe Biden administration would likely be easier than with Trump. Yet, the government should bear in mind that Trump could easily overturn the agreement. Various plans should be made under such a scenario," he added.

During his tenure, Trump pressed Korea for a fivefold increase in its share of defense costs, straining the decades-long bilateral alliance and significantly delaying the signing of a renewed deal.

Republican presidential candidate and former U.S. President Donald Trump greets supporters as he attends a rally in Schnecksville, Pa., April 13. Reuters-Yonhap

Now, with Trump seeking another presidential term and recent polls showing him in a neck-and-neck race with Biden, Korea is bracing for potential "Trump risk" in defense cost sharing.

"Even if the two sides manage to sign a deal earlier than anticipated, there are still concerns that if Trump gets reelected, he might just scrap it. It's not a far-fetched scenario, given his past tendency of disregarding already signed agreements with other nations if he deems them to be unfair to the U.S.," said Cha Du-hyeogn, a senior researcher at the Asan Institute of Policy Studies.

He also pointed out that it would be physically impossible to wrap up the negotiations before the U.S. presidential elections in November.

But the researcher highlighted potential advantages of initiating discussions ahead of schedule, such as addressing a broader range of issues that were often overlooked in previous negotiations, including increasing transparency in expenditures.

"This could also provide leeway for Seoul to make flexible demands, considering the significant concessions it made in the previous 11th SMA," Cha noted.

In the 11th SMA, reached in March 2021 during the Biden administration, the two sides settled on Korea paying 1.18 trillion won ($1.03 billion), marking a 13.9 percent hike from the previous agreement signed in 2019 — the third-largest annual rise for Seoul since the pact was created in 1991.

In that agreement, Korea consented to an annual increase rate of its share in defense costs to align with annual rises in its defense budget. This departure from the previous practice of correlating it with the rise in the consumer price index (CPI) was perceived by critics as imposing a heavier burden on the Asian nation.