China's civilian leaders, beginning with President Hu Jintao, are believed to want stable military relations with the U.S. so they can attend to pressing political and economic problems, such as unemployment. The PLA, however, sees U.S. forces as the enemy and thus has little incentive to strive for good relations.

A grudging balance appears to have been struck. The PLA reluctantly deals with the U.S. and slows the pace whenever it can. The civilian leaders, in turn, need the support of the PLA to stay in power and thus are reluctant to oppose the military leaders.

The current wrangle started just before Thanksgiving when the PLA abruptly said the aircraft carrier Kitty Hawk and accompanying vessels would not be permitted to sail into Hong Kong on a long-planned visit.

About 300 members of families of the crews had flown at their own expense from Japan, where the ships are based and crew families live, to Hong Kong to celebrate Thanksgiving. That distance is about that between New York and San Francisco, and airfare alone is about $500 a person.

Later, it turned out that the Chinese had also refused entry of two smaller ships, the wooden-hulled minesweepers Patriot and Guardian, when they sought to escape a storm at sea. Maritime tradition holds that politics are set aside and help is rendered when a ship is in trouble at sea.

Three American admirals, Chairman of the Joint Chiefs of Staff Mike Mullen, Chief of Naval Operations Gary Roughead and Pacific Commander Timothy Keating, all expressed public dismay at the Chinese actions.

A Chinese official at first said the refusal to allow Kitty Hawk to enter Hong Kong's harbor was due to a "misunderstanding." Another official, however, soon denied that, but no explanation has been forthcoming. Another U.S. ship, the destroyer Reuben James, has been denied a New Year's Day visit.

Hints from Beijing and speculation in the U.S. said the Chinese were angry over the recent visit to Washington by the Dalai Lama, the exiled Tibetan leader, and over arms sales to Taiwan. Some observers brushed those off as "not new." One said maybe the explanation was "simple bloody-mindedness."

Experienced China hands in the U.S. said the lack of coordination was perhaps the most troubling aspect of the issue. "There doesn't seem to be a central functioning channel, such as a national security council, for these issues," said one. Another agreed: "I see little evidence that the Chinese have successfully created or empowered any kind of structure to effect the necessary internal communication."

In Washington last week, the undersecretary of defense for policy, Eric Edelman, met with a PLA deputy chief of staff, Lt. Gen. Ma Xiaotian, to establish a dialogue on nuclear strategy. A Pentagon spokesman, Bryan Whitman, said U.S. officials expressed "disappointment" over the port issue, and "we have moved beyond it."

Besides the current issue, the Bush administration officials have questioned the purpose of China's expanding military budget. They have pointed to China's investment in naval and air forces that seem to be intended to deny U.S. forces access to the area around Taiwan, the island to which Beijing lays claim.

China has repeatedly said it would use military force to prevent Taiwan, which governs itself now, from acquiring formal independence. American law and credibility make it most likely that the U.S. would be required to respond with military force to China's military action.

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.