When two young boys square off in the school playground, they will often appeal to higher powers. “My big brother can beat up your big brother!” they cry out as a scare tactic. Even if the two kids don’t come to blows, one will still try to impress the other by claiming that his elder brother is stronger, richer, or more successful.

The two Koreas have been locked in this playground dynamic for decades. In the Korean War, the patrons of both sides — the United States and China — fought each other to a standstill.

In the years after, both Koreas depended on their larger and richer backers to help them rise from the ashes of the conflict.

Although the North has long accused the South of being a flunky of the United States, the North too has become heavily reliant over the last decade on its own patron, China, to provide food and fuel.

The Chinese economy and the U.S. military still cast very large shadows across the Korean Peninsula. The recent summit between Kim Jong-il and Roh Moohyun suggests, however, that the two Koreas are finally groping their way toward a fundamentally new regional order.

The 2000 summit broke the ice. At the 2007 summit, the two sides pledged to move toward a more integrated and self-reliant peninsula. The agreements at the summit fall into roughly two categories.

The economic agreements are an indirect signal to China; the security proposals send an indirect message to the United States. In both cases, the two Koreas aim to institutionalize the radical reversal in relations set in motion by the first summit.

The economic agreements are perhaps the more dramatic. The two sides will move to the next stage of the Gaeseong development, facilitate freight shipments across the border on new train lines, and construct joint shipbuilding works in Anbyeon and Nampo.

Perhaps more significantly, they will undertake a second joint industrial zone at Haeju Port. Stretching from the joint tourism resort at Mount Geumgang in the east through the Gaeseong zone and now to Haeju on North Korea’s west coast, a zone of cooperation will effectively replace the Cold War symbol of the Demilitarized Zone (DMZ).

The two Koreas are expanding economic cooperation under the watchful eye of China. Since the explosive growth of the Chinese economy, centered in the special economic zones in the south, Beijing has been angling to create another hub of economic growth in the northeast.

To that end, it has leased the North Korean port of Rajin and begun to invest in roads and energy in North Korea’s northeast.

The summit agreements amount to a rival version of regional development, a longterm vision of the two Koreas combining their comparative advantages to compete effectively against China.

The security agreements at the summit, meanwhile, anticipate an era in which the United States no longer calls the shots. The two Koreas expressed their desire to move beyond the armistice and toward a permanent peace regime.

They talked about establishing a common fishery zone to end the seasonal confrontations in the West Sea. And they promised to begin military discussions on confidence-building measures.

All of this challenges indirectly the foundation of the U.S.-South Korean military alliance. If Seoul and Pyongyang indeed reduce military tensions, then the primary rationale for U.S. forces in South Korea begins to evaporate.

North and South may well agree to maintain U.S. forces on a unified peninsula — to guard against Japan’s “normal” military — but America will nolonger play the overarching role of guarantor of the peace.

The recent summit, in other words, asserted a certain economic independence in the face of China’s overwhelming trade power and asserted a measure of military independence in the face of overwhelming American military power.