Although China tirelessly asserts it, there is not one China. There are, rather, four Chinas - the Communist mainland, Portuguese Macao, British Hong Kong, and Kuomintang-ruled Taiwan.
And, while Peking decides what to do with Macao and Hong Kong, it must keep a wary eye on Taiwan's reactions.
After the left-wing revolution in Portugal in 1974, there were those in Lisbon who imagined Peking would be delighted to take back Macao. The Chinese rejected it, making clear they alone would decide the right time for reversion.
It has been widely assumed that Peking realizes a Chinese takeover of Macao would have administered a serious, possibly fatal, blow to the business confidence of thriving Hong Kong, which, like Macao, was originally Chinese territory now ruled by foreigners.
Similarly, the Chinese Communists are presumably aware that to take over Hong Kong would reduce to the vanishing point the already slight chance that a future Taiwan government would negotiate reunification with the mainland.
A Chinese miscalculation on future arrangements for Hong Kong could send entrepreneurial talent, money, and refugees from Hong Kong to Taiwan - much as all three have come to Hong Kong from China since 1949. Apart from strengthening the island's economic prospects, this would put the seal on Taiwan separateness.
The effect on Taiwan could be more positive if Peking agrees to an arrangement whereby Chinese nationalism is somehow satisfied, but Hong Kong's separateness and economic growth are left untouched.
All this assumes China sees the linkages. Recent interplay between China and the US over Taiwan suggests otherwise.
In effect, China has tried to use Sino-American relations as a bludgeon with which to force Taiwan to the conference table. So, while China woos Taiwan with the thought that it can keep its own Army after reunification, it pressures the US to eventually halt all arms sales to Taiwan. This has only increased Taipei's hostility and suspicion.
The problem of the one-China linkage theory is that it could end up as a do-nothing argument: China allows Macao to continue in order to please Hong Kong and allows Hong Kong to continue in order to please Taiwan. This makes economic sense if China sees its interest in preserving the economic progress achieved by Hong Kong and Taiwan. It would make even more sense if, one day, China-Taiwan trade is as mutually profitable as China-Hong Kong trade.
But for emotional and nationalist reasons such an approach might be anathema to China. The temptation will be to try to make autonomy within China work for Hong Kong as an inducement to Taiwan, rather than having the patience to wait until Taiwan is ready for rapprochement.
Either way, China will be up against its past performance on the autonomy issue. In Tibet, for example, which had a 400-year history of separate cultural and political development prior to absorption in the People's Republic of China, the Chinese admit their oscillating policies have failed.
This failure has created deep skepticism in Taiwan and Hong Kong that Chinese policies would be relevant to their far more complex societies. They also know that what China means by autonomy is very different from the Western use of the term.