The next US president, whoever he is, will find that one of his pre-occupations will be China and Taiwan - and how to stop their war of words from becoming a full-blown conflict.
By Paul Reynolds
BBC News Online world affairs correspondent
A new exhibition of China's military power has been shown in Beijing
The latest verbal exchange between Beijing and Taipei raises a potentially new danger - that of Taiwan acquiring an offensive missile capability.
Taiwan's current defence policy is precisely that - defence.
If it decided to develop or buy ballistic or, more likely, cruise missiles - with which it could threaten Chinese cities - the delicate balance that now exists could be upset.
China might regard such weapons as a threat - or even an excuse for an invasion.
A $18bn US arms package agreed in 2001 is due to provide Taiwan with a series of defensive systems - four ex-US Navy destroyers, eight diesel submarines, 12 P-3 Orion anti-submarine aircraft and a number of anti-ship missiles, artillery pieces and helicopters.
Subsequently the US agreed to sell Taiwan the advanced Patriot anti-missile system PAC-3, which would be its main defence against any Chinese ballistic attack.
Taiwan's military is losing its technological advantage
The issue of an offensive capability was raised recently by Taiwanese Premier Yu Shyi-kun, who said that if China was able to attack cities in Taiwan, then Taiwan should be able to respond.
"If you attack Taipei and Kaohsiung, I should at least be able to strike Shanghai," he declared.
China accused him of "clamouring for war" and claimed that Taiwan was "obstinately carrying out splittist activities".
In Chinese Communist Party vocabulary "splittist" is about as bad as it gets. It means Taiwanese independence, something China will not accept.
According to Doug Richardson, editor of Jane's Missiles and Rockets, Taiwanese talk of missiles has been prompted by the military imbalance between Beijing and Taipei.
China has 500 ballistic missiles stationed opposite Taiwan, he says, and the build-up is clearly designed to deter Taiwan from declaring independence.
"It's pretty one-sided," Mr Richardson said.
He added that China was also testing its own cruise missile called Dong Hai-10, or East China Sea-10. Taiwan is in the East China Sea.
The United States is committed to defending Taiwan, but under a doctrine known as "strategic ambiguity" the nature of that defence was left unclear for years.
Certainly it included selling arms, albeit of a defensive type, but there was no commitment to going to war on Taiwan's behalf if China ever invaded.
The Bush administration sought to change "strategic ambiguity" into what it calls "strategic clarity".
President Bush made a statement in 2001 that the US would do "whatever it took to help Taiwan defend herself."
However at the same time, the US does not want Taiwan to declare independence. In effect, it wants the status quo to persist.
The Republican presidential election platform has restated this policy with the words: "America will help Taiwan defend itself."
But the Democrats are vaguer. "We are committed to a One China policy and will continue to support a peaceful resolution of cross-Straits issues," the party states.
Adam Ward, Senior Fellow at the International Institute for Strategic Studies in London, said the clarity sought by Mr Bush had not been entirely successful.
"Each side interprets it to its own advantage," he argued. "This will require continuing deep engagement by whoever is president."
The Pentagon also "muddied the waters" in a report to Congress in July about China's military strength, he added.
This report said: "Asymmetric capabilities that Taiwan possesses or is acquiring could deter a Chinese attack by making it unacceptably costly. Taiwan will most likely expand these capabilities either in tandem with or in lieu of improving its conventional forces."
The report specifically referred to types of weapons system.
"Taipei political and military leaders have recently suggested acquiring weapons systems capable of stand-off strikes against the Chinese mainland as a cost-effective means of deterrence."
"Leaders have publicly cited the need for ballistic and land-attack cruise missiles," it went on.
Even specific targets were mentioned.
"Proponents of strikes against the mainland apparently hope that merely presenting credible threats to China's urban population or high-value targets, such as the Three Gorges Dam, will deter Chinese military coercion."
Such comments sparked concern among analysts in the US.
David Lampton, a veteran China watcher at the John Hopkins School for Advanced International Studies and the Nixon Center (itself no friend of communist regimes) wrote in the Straits Times: "Offensive deterrence is a terrible idea for Taiwan."
"In moving in offensive directions, Taipei could well provide Beijing with a pretext for pre-emption," he stated.
Some observers hope that the recent change of command over the Chinese armed forces from Jiang Zemin to President Hu Jintao will reduce tensions.
Most analysts say that while the new Chinese leadership is not giving up a claim to Taiwan, it might be more patient in pursuing it.
The question is also whether Taiwan, too, will be patient - and not go for its own offensive weapons.