Bush will meet on Wednesday with President Lee Myung-bak, a conservative, pro-American leader who took office in February. Lee's approval ratings tumbled when he lifted a ban on U.S. beef despite public fears about its safety. The public outcry prompted street protests that drew attention worldwide earlier this year; Bush held off visiting Seoul around that time because of the unrest.
As Bush arrived on Tuesday evening, 30,000 people held an outdoor Christian prayer service to support him. His motorcade sped by pockets of people smiling and waving U.S. flags his way.
Later, an estimated 20,000 anti-Bush protesters gathered downtown. Riot police blasted them with water cannons as they tried to march onto the main boulevard. Police warned the crowd that the liquid contained markers to tag them so they could be identified later.
About 70 demonstrators were arrested downtown and 12 more were arrested near the military airport where Bush landed, police said.
"I don't have anti-U.S. sentiment. I'm just anti-Bush and anti-Lee Myung-bak," said Uhm Ki-woong, 36, a businessman who was wearing a mask and hat like other demonstrators in an apparent attempt to conceal his identity from authorities.
Despite the protests, the United States has a good standing with the Seoul government. The United States has quietly maintained a long-term troop presence in South Korea, now numbered at almost 30,000, since intervening in the 1950-1953 Korean War.
"The United States made sacrifices for South Korea during the Korean War and helped us live well," said Kim Jung-kwang, a 67-year-old retired air force colonel who wore his military uniform to the prayer rally. "The United States is not our enemy. Without the U.S., we will die."
Bush is on his ninth trip to Asia; this one is built around the Olympics in Beijing. Bush also will stop in Thailand.
The White House anticipated protests over the beef issue but sought to put them in perspective. U.S. beef has begun appearing again on the South Korean market and is selling.
"While there may be some who will protest, I think you need to look at what's happening on the supermarket shelves," said Bush's adviser on Asian affairs, Dennis Wilder.
The U.S.-South Korea bond has had other tests this year, too.
A trade deal Bush wants with South Korea has been buried by Congress. And a seemingly obscure change in how the U.S. classifies a set of islands drew widespread anger in South Korea, prompting Bush officials to abruptly reverse course.
Whatever the flashpoints, Bush and Lee are likely to emphasize the bigger picture -- an increasingly prominent partnership that both nations need.
The countries are at the heart of an international effort to rid North Korea of its nuclear weapons. Bush has indicated he will remove North Korea from the U.S. terror blacklist, but not unless Pyongyang allows its dismantlement effort to be verified. The White House is tamping down expectations about an Aug. 11 date by which North Korea is expected to agree to an inspection proposal.
Wilder said Aug. 11 "is not a deadline." He said the date will come and go without change for North Korea's status on the terror list if it doesn't respond favorably.
Bush comes with thanks to South Korea for contributing help in Iraq and Afghanistan. He was expected to ask Lee for more troops in Afghanistan, where violence is back on the rise.
Bush, to some degree, has gotten swept up in local frustration really directed at Lee.
Lee soared into office in February with the nickname of "The Bulldozer" and a businessman's reputation for results.
But Lee deeply angered his own people at that time by lifting the ban on U.S. beef, timed to his visit with Bush at Camp David, Md., in April. It was seen as an obvious attempt to curry favor with Washington and win support from members of Congress for the stalled free-trade agreement.
Lee later apologized, accepted changes in the beef policy and sacked some key advisers.