... Newly available documents from former communist-bloc nations have revealed the extent to which North Korea has long been an independent actor rather than a pawn in some larger struggle between communist and capitalist superpowers.

Even at the height of the Korean War, we now know, the alliance between China and North Korea was really a marriage of convenience, one fraught with tensions and disputes, rather than the true ideological partnership that most Americans believed it to be.

Little changed in the years immediately after the cease-fire. Things remained tense between China and North Korea, with leaders from the two sides rarely even speaking at diplomatic functions. Relations improved after the Chinese increased financial assistance to the North in the later part of the 1950s, but they declined again in the mid-1960s. Kim Il Sung banned Chinese propaganda, news and cultural exchange. Meanwhile Chinese officials in North Korea (DPRK) insisted that they would “observe the laws of the DPRK which they like and would not observe those which they did not like.” Leaders traded personal insults and denounced each other as criminals and worse: Kim, the Chinese Red Guard declared, was a “fat revisionist.” Violent skirmishes even broke out along the border in the late 1960s, with the Chinese Red Guard placing Korean casualties on a freight train they sent back across the tracks to North Korea, covered with graffiti declaring, “This will also be your fate, you tiny revisionists.”

Many factors underlay this tension, but at its heart was a basic reality that communist leaders recognized but that U.S. policymakers have still not accepted: North Korea was determined to resist Chinese influence on its policymaking under almost any circumstances.

The two sides made amends by the end of the 1960s, and relations never reached that nadir again. Still, they continued to have a largely utilitarian relationship based on mutual self-interest, coexisting for the next decades as independent nations that maintained autonomous policymaking objectives and a healthy distrust of each other.

The end of the Cold War and the blossoming of Chinese ties to the West strained things even further and reinforced the constraints on Chinese influence in Pyongyang. The North particularly saw China’s recognition of South Korea in 1992 as a betrayal. Economic ties persisted, but political relations continued to be strained. Leaked cables from the U.S. Embassy in Beijing reveal that in 2010, Chinese officials even told the American ambassador that their nation would accept Korean reunification under Seoul’s leadership but lamented that China had far less influence on the North than “most people believe.”

U.S. officials, however, continue to find this hard to accept. The North Korea problem could be solved, we have heard over and over again, if only China would do something! For the past few decades, the pattern has been simple and predictable: North Korea does something provocative. U.S. officials demand that China bring them to heel. China offers some empty words and gestures, but nothing really happens. So U.S. officials rail against China for its unhelpfulness and then retreat to their offices, where they actively hope that the problem goes away without actually doing anything about it. ...