The United States walks a fine line in its relations with China and Taiwan.

Recently the United States announced plans to sell $6.5 billion worth of arms to Taiwan — advanced weaponry and military items, including guided missiles and attack helicopters.

Predictably, the People's Republic of China was not amused.

China promptly notified the United States that it was canceling senior-level military and diplomatic visits and other military-to-military plans.

Marine Maj. Stewart Upton, a Defense Department spokesman, said that "China's continued politicization of our military relationship results in missed opportunities."

"It's an unfortunate step," said Robert Wood of the State Department.

But we should have expected as much. China, which views Taiwan as a breakaway province, said the sale interferes with internal Chinese affairs and endangers its national security.

The Chinese have canceled a visit to America by a senior Chinese general, other similar trips, port calls by naval vessels and meetings on stopping the spread of weapons of mass destruction.

But Beijing will still participate with the United States in six-nation talks to persuade North Korea to halt its nuclear weapons program and in the international effort to halt Iran's nuclear march.

The United States has protested that it is only upholding the Taiwan Relations Act which commits Washington to make available items Taiwan needs for defense.

The Chinese are not buying it. But at least their response was measured. They are still working with the United States on some endeavors.