The relationship between Washington and Beijing continues to look like the peaks and valley's of a stock market chart.
The latest dip, not surprisingly, is over Taiwan.
The vicissitudes of the relationship between the world's most powerful nation and the most populous nation can be seen in the swings during the past 12 months.
The incoming Bush administration was furious when Beijing dawdled in releasing the 23-member crew of the EP-3E plane, forced to land on a Chinese air base. The incident played into a new, harder line of US strategic thinkers brought in by the Bush team, who view China as a potential future "threat" to US security.
Yet behind the scenes, Chinese officials spent most of the past year trying to mend the damage. Especially after Sept. 11, China has cooperated in unprecedented ways with US intelligence gathering in Central Asia, and has worked for warmer relations with a country whose joint ventures finance a large percentage of China's dazzling economic gains.
President Bush's visit here last month, for example, earned state-run media headlines like "Bush visit full of eastern promise." Mr. Bush's time in Beijing brought cordial smiles and handshakes, if not much substantial agreement.
But now the smiles in Beijing are gone, and the press has turned sour largely over US treatment of Taiwan, the issue that is the No. 1 preoccupation among China's leaders.
"We are on the verge of another setback in SinoUS ties," intoned an editorial in the English-language China Daily last week. "A freezing wind is blowing," read a commentary in the official Xinhua news agency.
Communist China claims Taiwan as its own, even as the island of 23 million peoplecontinues to develop a democratic identity. China feels the White House is tacitly approving what it calls Taiwan's move toward "gradual independence."
Last month the first visa was granted by the USto a Taiwanese official since 1979 to Taiwan Defense Minister Tang Yiau-ming, who met senior Bush officials at a conference in Florida.
Later this month, the American Enterprise Institute, a US think tank, will hold a conference on Asian security that will include Japanese and Taiwanese officials, and be attended by US senators and congressmen.
US officials have said that an affirmative policy toward China does not mean the suspension of the Taiwan Relations Act, by which the US supplies weapons to Taiwan.
"China really does need and want good US relations. It can't afford to put itself in the position right now of having other nations choose between it and the US," says a Beijing-based scholar. "About all Beijing can do is protest."
This it has done. Twice in the past month, the Chinese have summoned US ambassador Clark Randt for "solemn representations" once over the visa question, and again when a US Pentagon report listed China along with Russia, Iraq, Libya, North Korea, Iran, and Syria as nations that the US had targeted with nuclear weapons as part of a response contingency.
The report detailed three scenarios about when the weapons could be used. One of those contingencies was a military confrontation between China and Taiwan.
A Taiwan newspaper, quoting a military report, said yesterday that it opposes any use of nuclear weapons by the US against China. The defense ministry said that the use of nuclear weapons in settling the Taipei-Beijing dispute would destabilize ties between Taiwan, China, and the US.
News of China's inclusion on the nuclear list prompted Vice-Foreign Minister Li Zhaoxing to say: "Where does the US want to lead China-US relations? The Chinese people will never yield to any outside intimidation, including nuclear blackmail."
Yet while US stock is low at the moment in China, it hasn't hit bottom. In fact, Chinese Vice-President Hu Jintao, regarded by many as the heir apparent to President Jiang Zemin, is still planning to visit the US later this month. Mr. Hu, favored by the late Chinese leader Deng Xiaoping, has long remained in the shadow of Mr. Jiang. Hu may well replace Jiang later this year, and his visit is regarded as important for US-China relations.
White House officials stated yesterday that they would firmly defend with Hu their right to sell arms to Taiwan and to meet privately with Taiwanese officials.
"We have done nothing wrong, and Beijing is going to have to learn to live with it," said Taiwan's South China Morning Post, quoting a senior official yesterday.
Some US observers of China, however, worry that hard-line US "China threat" security thinkers may not know where to draw the line, even while seeming to expand it.
A colonel in the Chinese Army, speaking for what he described as the mainstream view in the People's Liberation Army, told a Western reporter last week that "China no longer sees the US as an enemy. What we don't know is whether the US sees China as an enemy."
Material from wire services used in this report.