US strategic interest in Taiwan has grown in step with China's advancing military modernization and increasing assertiveness. Yet some argue that the cross-Strait dispute is a relic of the Cold War--that there's no reason that Taiwan should continue to be a source of tension in US-China relations.

Many of these commentators point to Taiwan and China's closer economic ties, arguing that the two sides are willingly pursuing political integration. Cross-Strait tensions are certainly easing--why should Washington let a problem that's resolving itself continue to challenge US ties with Beijing?

"The United States should be more vigorously supporting its long-time democratic friend and partner." -- Michael Mazza

Proponents of this line of reasoning ignore the fact that the PLA has continued its fast-paced build-up of missiles across the Strait in spite of greater economic integration.

One critic of the current state of the US-Taiwan relationship recently warned of the negative consequences should the United States 'interfere in the final stages of the Chinese civil war by backing Taiwan.' But it seems odd to advocate in favour of an autocratic regime at a time when freedom-seeking peoples are overthrowing despotic rulers across the Middle East--even more so when one considers that, unlike in the Arab world, China exists in a region where democracy has already taken root.

That aside, the argument that the United States is taking Taiwan's side is anyway less clear than many think. Yes, Washington has continued to sell defense items to Taipei. But both the George W. Bush and Obama administrations have also refused to sell those weapons that Taiwan most needs. During the Chen Shui-bian administration, Washington was adamant in its insistence that Taiwan not take any steps towards formal independence. More recently, Obama made significant concessions to Hu Jintao on Taiwan in their joint statement of 2009.

Indeed, Washington's mistake is in not taking a clear side in the cross-Strait dispute. The United States should be more vigorously supporting its long-time democratic friend and partner. There are clear strategic reasons for doing so--reasons that are only growing in importance.

Not least of these is the increasing importance for the United States to been seen as both a reliable friend and a supporter of democratization. As China rises and puts increasing pressure on its neighbours--many of whom are US allies--it's essential that those allies consider the United States to be a dependable security partner. Without that assurance, the region is more likely to descend into unwanted and unnecessary arms races, as countries work on their own to balance China and potentially each other as their military might grows.

Moreover, Taiwan's continued existence as an independent, democratic state--and US support for it--can provide succour for liberals in China, who want representative government for their own country. Since the end of World War II, Americans have found that the spread of liberal democracy in Asia has benefitted their interests. An imposed reversal of liberalization in Taiwan would benefit no one but the Chinese Communist Party.

From an American point of view, there is, of course, a military-strategic imperative as well for Taiwan's continued de facto independence. An annexed Taiwan almost certainly becomes a militarized Taiwan, home to both PLA air and naval bases. For China, the benefits of such bases are threefold. First, in the event of conflict in East Asia, the 'unsinkable aircraft carrier,' as Douglas MacArthur referred to Taiwan, will provide mainland China with strategic depth that it currently lacks. Any US forces steaming into the region will have to contend with Chinese military aircraft and naval vessels operating from Taiwan. Neutralization of bases on the island will likely be necessary prior to pursuing other primary objectives, thus complicating US calculations and military planning.

Second, an annexed Taiwan will allow China to easily threaten Japan's southern flank, including US bases on Okinawa. Clashing strategic, economic, and nationalistic interests foreshadow a more antagonistic future for Sino-Japanese relations, and while Japan has foresworn the use of violence to settle international disputes, China most certainly hasn't. It will be much more difficult for Japan to defend itself--and for the United States to defend its ally--if the islands face PLA threats emanating from Taiwan, from China's east coast, and, perhaps one day, from the east coast of North Korea.

Finally, control of Taiwan will enable the PLA to more easily exert control over the Luzon Strait, the waterway connecting the South China Sea and the Philippine Sea. Control of the Strait is necessary for China to achieve its dual goals of enforcing its claims to sovereignty over the South China Sea and of keeping foreign military forces out of that body of water. Control of Taiwan and the Luzon Strait, moreover, will for the first time grant the PLA Navy easy access to the Philippine Sea and the Pacific Ocean beyond, providing China even greater strategic depth and, for the first time since 1941, allowing an Asian power to threaten Guam and Hawaii.

Taiwan isn't a relic of the Cold War. Rather, it is situated at the geographic forefront of the strategic competition that very well may define the 21st century--that between the United States and China. The United States has long pursued a policy in Asia in which it provides security while promoting economic and political liberalization. The Taiwan of today is in many ways a fruit of that policy. Washington would soon regret any decision to drop its support for Taiwan and allow mainland China to annex the island nation. Only by continuing to nurture its relationship with Taipei and by continuing to steel the island against threats from the mainland can the United States hope to ensure continued peace in Asia.

Michael Mazza is a senior research associate at AEI.