SEOUL, Korea - The visit last month of North Korea's diminutive dictator Kim Jong Il to China is still making waves here in the South Korean capital.

The Chinese rolled Kim through showcases of their market reforms. The North Korean leader, who once denounced the Chinese for retreating from socialism, responded with dutiful words of praise for the Chinese model.

South Koreans applaud any evidence that Kim may be headed down a Chinese-style path. Like the Chinese, most South Koreans believe this may be the only way to ultimately persuade the North to abandon its nuclear weapons program.

But in conversations here with senior South Korean officials and others closely involved with North Korea, I detected unease, even alarm, at the growth of China's influence and presence in the North. Some talked darkly about a Chinese "takeover'' of the North.

South Korean mixed feelings about China are not new. But the Kim visit comes on top of a rapid broadening of Chinese economic ties to North Korea, described in detail in a new report issued by the International Crisis Group. Chinese trade and investment in North Korea has reached $2 billion annually. Bridges and highways in and out of North Korea are being built, making it easier to ship iron ore and other raw materials out.

Hundreds of Chinese firms are investing into North Korea, in some cases grabbing deals away from South Korean companies.

Is China willing to use this expanded influence to compel Pyongyang to give up nuclear weapons? Some in the Bush administration still cling to that hope. But the report argues strongly against that happening.

China may again drag Pyongyang back to the stalled six-party talks that it hosts. And it will move quickly to curb any North Korea provocation, such as a nuclear test, that could lead to war.

But China has an overriding interest in stability as well, opposing any attempt to destabilize the Kim government. The Chinese will cooperate to curb Pyongyang's laundering of counterfeit money through their banks, the report says, but will not shut down the North's banking operations in China.

South Koreans don't differ with China on the need to engage the North. Their own economic ties with the North are deepening. And Seoul too is consumed with the danger of triggering a war by trying to cut off the North's economic lifeline.

But South Koreans now also worry that China's deepening stake in the North will only perpetuate the division of the Korean Peninsula.

A South Korean businessman who is deeply engaged in dealings with the North argued to me privately that the North Koreans are unhappy with their dependence on Beijing and eager for an alliance with the United States. By refusing to deal directly with Kim Il Jong, he argued, "the Bush administration is pushing North Korea into the camp of China.''

We should explore such claims with a healthy dose of skepticism. The North Koreans are masters at playing the Chinese and South Koreans against each other, as they did with the Russians and Chinese during the Cold War.

More important, South Korean nervousness about China comes together with renewed interest in shoring up the strained alliance with the United States. This is partly behind a decision to negotiate a free-trade agreement (FTA) with the United States this year.

A free-trade agreement between the United States and Korea, one of the largest economies in the world, would be good for both economies. It should open more markets in Korea, removing a host of barriers such as restrictions on foreign investment. Korean officials, led by a young and ambitious American-trained trade minister, believe an FTA will spur a new round of needed internal reform and a jump in growth.

Anti-FTA protests were already taking place as I was discussing this with Korean officials. More are sure to come from those, such as farmers, most threatened by more open markets. But officials say the president and his government are committed to pushing this through.

Privately, Korean officials hope the FTA will also remind Koreans and Americans of the value of their alliance. It gives both sides something to talk about other than to dwell on their differences over North Korea. We should push hard from both sides to quickly finish an FTA deal -- and continue to talk quietly about our shared interests in maintaining a strategic balance in Northeast Asia.

What is South Korea's strategic posture in East Asia?

After the Korean War ended in 1953, South Korea and the United States established a political and security alliance that has lasted more than half a century. "For a number of decades, South Korea primarily defined itself as a U.S. ally, with the enemy to the north," says Donald Gregg, president of the Korea Society and a former U.S. ambassador to Korea. However, South Korea is now trying to create a new role for itself in Asia. Seoul is exploring a growing economic relationship with China--which passed the United States in 2003 to become South Korea's largest trading partner--and its policy of engagement and growing cooperation with North Korea is pulling it away from the United States. "All we know for sure is that South Korea's role is no longer junior partner to the U.S.," says David Kang, a visiting professor of Asian studies at Stanford University. "The days when they would just unquestioningly follow the U.S. are over."

Kang and other experts say Seoul is beginning to shift its focus towards increasing regional ties with its Asian neighbors. The U.S.-South Korea relationship, while still strong, is not as exclusive as it has been in the past. "South Korea is still an ally of the United States ... nevertheless, it has been the most active country in promoting East Asian cooperation and integration, and will probably continue to do so," says Charles Armstrong, professor of history and director of the Center for Korean Studies at Columbia University.

What are South Korea's biggest foreign policy challenges?

Dealing with North Korea while preserving its relationship with the United States, maintaining relations with Japan, and addressing potential long-term military or economic threats from China, experts say. But "the major issue for Seoul is overwhelmingly North Korea, and everything else gets filtered through that lens," Kang says. South Korea looks to its northern neighbor with the goal of eventual reunification, and therefore seeks economic cooperation and political engagement to smooth relations and slowly move down that path. The United States, on the other hand, is primarily seeking to prevent North Korea from gaining nuclear weapons, and has refused to engage with Pyongyang until that issue is resolved.

Other experts see a disconnect between how South Korea views its role in the region and how other nations see it. South Korean officials talk of playing a "balancing" or mediating role in regional disputes, including tensions between China and Japan and the nuclear standoff between the United States and North Korea. But South Korea's "actual ability to mediate and balance is limited," says Armstrong. And while South Korean President Roh Moo-Hyun has expressed hopes of building Seoul into a logistics and business hub for the region, existing tensions on the peninsula--including international fears that North Korea is amassing a nuclear arsenal--cloud any long-term economic plans. As things stand, South Korea has the world's 11th largest economy, but not a corresponding level of political clout.

How is South Korea dealing with North Korea?

Through a policy of active engagement. In 1998, Former President Kim Dae-Jung introduced the "Sunshine Policy" aimed at improving ties with North Korea while assuring Pyongyang that Seoul is not trying to absorb it. Since then, "the degree of economic interaction between south and north has substantially increased," Armstrong says. Kim and North Korean President Kim Jung-Il met at a historic summit in 2000, and increasing progress has been made on a range of issues, from economic--increased rail links and joint projects like the Gaesung industrial complex--to social and symbolic, including cross-border family visits and Korean athletes marching together under a single flag at the Olympics. Trade between the two countries reached $697 million in 2004, and South Korea is now Pyongyang's second-largest trading partner after China.

South Korea sees engagement with North Korea as yielding far more benefits than confrontation. "South Korea is reorienting itself toward reconciliation and eventual reunification of the peninsula," Gregg says. South Korean officials say reunification would reduce the burden on each side of maintaining huge armies, help improve living standards, draw international investment, create employment, and help avert the worst possibility: open war on the Korean peninsula.

What is South Korea's relationship with China?

South Korea is developing increasingly warm relations with its giant western neighbor. "There is a real fascination with China in South Korea, and the flow of investment, exports, students, tourists, and businessmen going to China from South Korea has exploded in the last several years," Armstrong says. Bilateral trade between Seoul and Beijing reached $90 billion in 2004, a 42 percent increase from 2003. The two countries also agree politically on issues ranging from opposition to Japanese Prime Minister Junichiro Koizumi's visits to the Yasukuni war shrine, to accord on how to deal with North Korea's nuclear ambitions. China is also choosing the path of engagement with North Korea, and helping Pyongyang find a "Chinese way" to develop: that is, increasing economic openness without sacrificing political control. "On the whole, [South Korea and China] see pretty much eye to eye on the major geopolitical issues," Kang says.

Beijing, like Seoul, is investing in North Korea, which has ample natural resources--including coal, iron, and gold--and a low-cost labor force. In 2003, Chinese investment in North Korea was $1.1 million; in 2004, it ballooned to $50 million; and in 2005, it was expected to reach $85-90 million. The volume of trade between China and North Korea reached $1.5 billion in 2005, making Beijing Pyongyang's largest foreign trading partner. North Korean leader Kim Jung-Il, who rarely travels, emphasized Beijing's importance to his country by visiting China in January.

South Korea is positioning itself to be closer to an ascendant China, but trying to do it without jeopardizing existing ties with the United States. South Korea's biggest worry, experts say, is being pulled into a conflict between the United States and China over Taiwan.

What's the relationship like between South Korea and Japan?

"Very bad at the moment in terms of public diplomacy and popular opinion," Columbia University's Armstrong says. South Korean wariness of Japan dates back at least to 1910, when imperial Japan invaded Korea and ruled it as a colony for thirty-five years. During the occupation, Japanese efforts to suppress Korean language and culture earned Korean enmity. During World War II, the Japanese practice of using "comfort women"--women from occupied countries, mostly Korea, who were forced to serve as prostitutes for the Japanese army--increased the anti-Japanese feeling.

South Koreans, and others across the region, are also infuriated by Koizumi's annual visit to the Yasukuni shrine. The site honors more than two million Japanese war dead, but includes the remains of more than a dozen convicted war criminals. South Korea also has disputes with Japan over territory. Both countries claim a group of islands--and the fishing and mineral rights around them--in the Sea of Japan that the Koreans call Dokdo and the Japanese call Takeshima. And many critics in South Korea and across Asia accuse Japan of whitewashing its wartime atrocities in its grade-school textbooks.

But much of the South Korean conflict with Japan may be for domestic political consumption, some experts say. "Under the surface, I would say the degree of interaction [between Seoul and Tokyo] remains high and, in the economic realm, is rather good," Armstrong says.

How is South Korea dealing with the United States?

While experts say most South Koreans still consider the U.S.-Korean alliance the backbone of their security relationship, time has passed and attitudes are shifting. A new generation of South Koreans, assertive and nationalistic, are less mindful of the Korean War--and less grateful for American intervention in the conflict that left nearly three million Koreans dead or wounded--and more resistant to what they see as a U.S. attempt to impose its values and Washington's singular focus on terrorism. The United States has opposed South Korean engagement efforts with North Korea, and has also moved to increase its ties with Japan. The Bush administration's foreign policy, including the war on terror, its punitive stance toward North Korean nuclear weapons, and particularly the invasion of Iraq, is highly unpopular in South Korea, according to opinion surveys there.

South Koreans are also increasingly demanding more control over their country's military and political affairs. In 2004, the United States returned several military bases to Korean control, and agreed to withdraw 12,500 of the 37,500 U.S. troops currently stationed in Korea by 2008. U.S. officials, including Defense Secretary Donald Rumsfeld, had been pushing for South Korea to take more of a role in the defense of the Korean peninsula, to free up U.S. forces for deployment elsewhere. But, all differences aside, Seoul is still eager to cooperate with the United States. South Korea, with some 3,000 troops in Iraq, is the third-largest member of the U.S.-led coalition there, behind the United States and Britain.

What is the recent history of the region?

Poised between China and Japan, fought over by the United States and Russia, the Korean peninsula long has played a central role in Asia's geopolitical affairs. After World War II, Japanese colonial rule gave way to U.S. and Soviet trusteeship over the southern and northern halves of Korea, respectively. The peninsula was divided at the 38th Parallel. In 1948, the southern Republic of Korea and the northern Democratic People's Republic of Korea, under Kim Il-Sung, were established.

In 1950, North Korean forces invaded South Korea, starting a conflict that brought in China on the North Korean side and a U.S.-led UN coalition on the South Korean side. While an armistice was agreed to in 1953, a formal peace treaty was never signed. In 1954, the United States agreed to help South Korea defend itself against external aggression in a mutual defense treaty. U.S. troops have been stationed in Korea since then. In addition to this important security relationship, shared interests in the last fifty years have included fighting communism and, since the 1980s, establishing a strong democracy and fostering economic development. However, in recent years strain has emerged on a range of issues, none more important than how to handle Pyongyang.