Writing about Gibraltar, Thomas D. Grant says,

The People’s Republic of China (prc) demands control over Taiwan. In this seemingly nonnegotiable position, the prc draws from the same legal well as Spain in demanding Gibraltar. Both argue that the doctrine of territorial integrity trumps the right of self-determination, so Taiwanese and Gibraltarians alike can have no say in what happens to the lands they call home. The final disposition of the two territories, in the Chinese and Spanish views, is automatic, not democratic. And the automatic result that their reading of the law and history dictates is reversion.

Territory in an international context, however, is no longer a thing to be traded freely without reference to the rights of incumbents well-installed there or disposed of according to ancient parchments. Rights to territory with no existence outside the abstraction of treaties or historical arguments do not translate into a case for contemporary control. In the modern understanding, where an old claim has had no practical reality on the ground for a very long time — admittedly, international law leaves uncertain exactly how long — it seldom, if ever, can spring up to claim some afterlife. The Beijing and Madrid views are archaic and run against modern international law.

They also, intertwining, reinforce one another. Giving in to Spain’s claim to Gibraltar bolsters Beijing’s most intransigent demands over Taiwan, even possibly provoking an aggressive lurch where America wisely has long urged care and tact. Anybody doubting whether China would notice the fate of the rock should recall that Beijing’s lawyers and strategists watched carefully to see what happened to Argentina’s similar territorial integrity arguments 20 years ago in the Falklands. Argentina claimed that its ancient rights to title to territory, notwithstanding generations of dormancy, nullified any present-day rights of Falkland Islanders to determine their own fate. When Argentina attempted to convert this theory into practice, it met fierce resistance from Margaret Thatcher’s Britain. The overwhelming majority of bystanders either accepted the uk position tacitly or applauded it. China’s grand strategists had to go back to the drawing board, the legitimacy of a wanton strike across the Taiwan Straits having been cast into serious doubt.

The United States has consistently maintained that the prc must not resort to military means to bring about a settlement of its differences with Taiwan — and has not ruled out use of force in response to an assault on the island democracy. The United States, moreover, has expressed the view that preservation and promotion of the democratic nature of Taiwan constitutes a priority of American policy in the East Asia region. The Bush administration in particular has reiterated and reemphasized the American position that Taiwan-China relations must take place in a peaceful framework and with respect for the democratic and self-governing nature of Taiwan.

(Emphasis mine; link via Tyler Cowen.)