And China itself, now undergoing reforms that by its standards are benevolent, could go horribly wrong. For all Taiwan's development and democratisation, it still lives in the lengthening shadow of the mainland. If China also democratises and continues to develop, it will be harder for Taiwan to find fervent anti-communists to count as friends. Conversely, if China turns vicious, Taiwan's dabblings with independence look unsafe. As long as Taiwan remains top of the mainland's wish list, the desires of the 22m people on the island will always be tempered by those of the leadership in Beijing.
China reforms enough for the two to agree to unify peacefully.
Its good behaviour in Hong Kong, if kept up for five or ten more years, will start to put Taiwan' s and the world's mind at rest about the notion of one country, several systems. China reforms even more, letting Taiwan go. By leaving Hong Kong's system alone, China has made itself vulnerable to infection from the free-wheeling territory. Already most of Guangdong, the province just across the border, is almost as exuberantly capitalist as Taiwan, not least because it is full of Taiwanese and Hong Kong firms. This could spread, along with the virus of democracy.