Vice President Mike Pence will arrive in Seoul Sunday, flying into a geopolitical maelstrom amid a possible North Korean nuclear test and harsh US warnings about a military response.
Pence's first visit to South Korea -- part of an Asia swing that also includes stops in Japan, Indonesia and Australia -- was conceived months ago, but could hardly come at a time of higher tension.
In the last week, geo-spatial imaging showed North Korea possibly preparing a nuclear test, to coincide with the 105th anniversary of the birth of founder Kim Il-Sung.
US President Donald Trump has warned that North Korea will be dealt with and officials have confirmed that military action is being considered, although has not been approved.
That issue will be top of the agenda when Pence begins talks with South Korea's interim Prime Minister Hwang Kyo-Ahn on Monday, and in Tokyo during talks with Prime Minister Shinzo Abe.
Both Japan and South Korea are firmly in the firing line and will want to caution against any US military action that could prompt a broader conflagration.
Away from immediate security matters, Pence will try to reassure allies concerned about Donald Trump's commitment to decades old security guarantees and protectionist rhetoric.
US officials acknowledge Trump's message of "America first" has at times been read by allies as meaning "everyone else last."
Pence's message will be that America's security and economic commitments are enduring and "ironclad," according to a senior White House foreign policy advisor.
That commitment, aides say, will be underscored by Pence's very personal ties to South Korea.
Sixty-four years ago to the day, his father, Lieutenant Edward Price was awarded the Bronze Star for valor in the Korean War.
In Seoul, Pence will try to steer clear of South Korea's tumultuous domestic politics ahead of elections next month. He is not expected to sit down with opposition leaders who could take the reins next month.
But he will no doubt address worries in Washington that any new government may slow-walk the deployment of THAAD -- a system designed to shoot down missiles from North Korea or elsewhere.
The United States has almost 30,000 troops in South Korea and is keen to see the project fully deployed.
The issue has been complicated by China's furious opposition to the prospect of having a high-tech radar system on its doorstep, fearing it could partially neutralize its nuclear deterrent.
Beijing has responded though diplomatic pressure and economic coercion, that has soured relations with Seoul.
But Pence, whose public message at times seems at odds with Trump's, will have plenty of work to do to reassure South Korea that the United States is a reliable partner.
Trump has repeatedly complained that the United States shoulders too much of the burden for other countries defense and has suffered under bilateral and regional trade agreements.
An agreement on who pays for US troops in South Korea is due to expire next year, and South Korea -- where anti-US sentiment is high -- could be asked to pay more.
Trump has also called for a review of all bilateral trade agreements, including the five year old US-South Korea deal -- or KORUS.
The new US president's relentless focus on trade deficits, has some of the deal's supporters dismayed.
"There is not a valid reason to be concerned about KORUS" Wendy Cuttler, who helped negotiate the deal told a Korea Society event this week.
"I don't think its correct to judge the success of a trade agreement on the basis of a bilateral trade deficit."
According to Cuttler, the deficit has more to do with steady US economic growth that has raised demands for Korean imports.
Others point to tens of billions of dollars worth of South Korean investment into the United States, that have created an estimated 50,000 jobs.