With his approval rating rising to over 50 percent this week, U.S. President Barack Obama told visiting Chinese top leader-in-waiting Xi Jinping that Washington welcomes China’s “peaceful rise” but cautioned him about friction over trade and human rights issues as the economic and military rivalry grows between the two countries.

While the Chinese vice president was seeking to boost his international standing with his four-day visit to the United States, it offered U.S. leaders to size up the man likely to lead the world’s most populous superpower through the next decade. Xi, 58, is expected to take the helm of the Chinese Communist Party this year and then will assume the presidency in March 2013.

Obama is under the election year pressure to be tough on diplomacy. He conveyed to the Chinese leader his dissatisfaction with Beijing’s pursuit of trade rules, undervaluing of the yuan currency, repression of the people of Tibet and Xinjiang, crackdown on human rights advocates and non-cooperation on global issues such as Syria. “With expanding power and prosperity also comes increased responsibilities,” he told his guest at the White House.

Xi did not directly respond to Obama’s criticism but expressed hope for a “cooperative partnership based on mutual respect” and emphasized the need for resolving economic disputes through dialogue instead of protectionism.

As we watched Xi’s tour of Washington, Americans from President Obama on down, dazzled by China’s “extraordinary development” over the past two decades, were unsure whether to regard the Asian giant as friend or foe. That uncertainty is also shared by South Koreans who are increasingly engaged with the Chinese in all areas.

This year marks the 20th year of South Korea’s diplomatic ties with China, an adversary in the Korean War in which the South fought in an alliance with the United States. That military alliance continues until today, with the U.S. keeping sizeable ground and air forces on our territory. Meanwhile, Seoul and Beijing have steadily upgraded their relations to a “strategic cooperative partnership.” China has overtaken the U.S. to become Korea’s largest single trading partner.

Yet, China maintains its alliance with North Korea and has acted as Pyongyang’s only guardian, providing economic aid vital for the North’s survival. Under the 1961 Treaty of Friendship and Cooperation and Mutual Assistance, China is obliged to intervene automatically when North Korea comes under an external aggression and should provide military and other assistance without delay.

The relations between Beijing and Pyongyang had turned sour when China normalized ties with South Korea in 1992 in what the North complained as a violation of the friendship treaty. But the two neighboring communist countries had too many geopolitical reasons to remain estranged, primarily the North’s economic needs and China’s regional security concerns. Despite their mended relations, Beijing has not provided military equipment to North Korea, nor has it conducted any joint military exercise with the North.

Liberals in Seoul, as they took power late in the 1990s explored direct avenues of approach to North Korea. The Roh Moo-hyun government went further, offering a “balancer’s role” between the Pacific forces of the United States and Japan and the continental forces of China and Russia. Domestic security agenda in Seoul continue to revolve around maritime and continental engagements.

China’s fast rise, unprecedented in modern history, has stirred external policies of nations and is forcing all regional players to redefine their diplomatic priorities. The Republic of Korea is faced with perhaps the most complicated impact of China’s changing status with its nearly absolute influence on North Korea. The ultimate national goal of reunifying the Korean Peninsula is to depend to a great extent on what strategic decision Beijing makes for the future.

South Korea is coming to a crossroads, two superpowers vie over the Asia-Pacific region in the not too distant a future. But we should avoid by all means the split of domestic politics along the lines of pro-continental and pro-maritime strategies. It will be dangerous and reckless for any future holders of power to try to choose between them. What is required under any circumstances is to maximize the nation’s economic, military and diplomatic abilities to pursue national interests.