South Korea's President Yoon Suk Yeol will be seeking US assurances on deterring North Korea when he meets President Joe Biden this week, while the Americans will likely be looking for Yoon's support for US interests related to China and Russia.
The conservative Yoon has made bolstering South Korea's alliance with the US a priority since taking office last year in the face of North Korea's relentless development of its nuclear arsenal.
Yoon is making the first state visit to the United States by a South Korean leader since 2011. Following are likely agenda items during his summit with Biden on Wednesday.
NORTH KOREA
US and South Korean officials have agreed to strengthen "extended deterrence", referring to the ability of the US military to deter attacks on its allies, given the worries over North Korea's growing military capabilities.
Yoon has been pushing to increase South Korea's say in operating "extended deterrence" while calls are growing in South Korea for it to develop its own nuclear weapons.
At the summit, Biden will pledge "substantial" steps to underscore the US commitment to deter a North Korean nuclear attack, a senior US official said.
The two countries are also likely to expand their security partnership in new areas like cybersecurity, Kim Tae-hyo, a senior security adviser for Yoon told reporters.
US-CHINA TECH TENSIONS
South Korean tech giants are concerned about being hurt by US efforts to block China's acquisition of foreign technology. The US government has granted South Korea's Samsung Electronics (005930.KS) and SK Hynix (000660.KS), the world's two biggest memory chipmakers, a one-year waiver to supply chip equipment to their production facilities in China, but it is not clear what will happened after it expires in October.
The US asked South Korea to urge its chipmakers not to fill any market gap in China if it bans the US memory chipmaker Micron Technology Inc (MU.O) from selling chips, the Financial Times reported on Sunday.
Yoon's office said his US trip would offer a chance to increase cooperation on high-tech supply chains.
UKRAINE
South Korea, a major producer of artillery ammunition, wants to avoid antagonizing Russia due to commercial interests and its influence over North Korea, despite mounting Western calls for help with the supply of weapons to Ukraine.
However, Yoon has recently suggested a willingness to provide weapons to Ukraine, more than a year after ruling out lethal aid.
South Korea has agreed to lend the United States 500,000 155mm artillery shells that could give it greater flexibility to supply Ukraine, a South Korean newspaper has reported. South Korea's defense ministry said the allies have been exploring ways to support Ukraine but declined to confirm specific discussions.
TAIWAN
South Korea has been playing a balancing act between the US, its main ally, and China, its largest trade partner, but Yoon has been outspoken on tensions in the Taiwan Strait.
In a recent interview with Reuters, Yoon said the Taiwan issue was a global one and he opposed any change in the status quo by force. His comments prompted an angry exchange of words between Beijing and Seoul with South Korea summoning the Chinese ambassador.
South Korea's comment on Taiwan was "the worst" since the establishment of diplomatic relations between China and South Korea in 1992, China's state-run Global Times said on Sunday.
The United States is likely to want South Korea to show more clarity in siding with the United States on Taiwan rather than engaging directly in military matters, given South Korea's own security concerns about North Korea and China, analysts say.