Written by Joseph Bosco.

When Japan bombed Pearl Harbor on December 7, 1941, it also simultaneously attacked the Philippines, triggering World War II in the Pacific. It was the opening salvo in the Japanese Empire’s campaign to invade and subjugate Southeast Asia in pursuit of its Greater East Asia Co-Prosperity Sphere.

The air assault was launched from the island of Taiwan which was then under Japanese military rule. Taiwan was the jumping-off point for the attacks on both the Philippines and the Dutch East Indies (now Indonesia). Throughout the war, it served as the staging area and major supply base that sustained Japan’s armies in Southeast Asia and as the control point for all shipping through the Taiwan Strait. The U.S. State Department at the time stated that based on strategic factors, with the exception of Singapore, no other location in the Far East occupied such a controlling position.

“Controlling Taiwan would facilitate China’s operations in the South China Sea and enable it to assert its territorial and maritime claims even more aggressively against the Philippines, Vietnam, Malaysia, and Brunei. Suddenly, China’s sweeping “nine-dash line” would become even more real and more easily enforceable by Beijing.”

Taiwan is situated at the edge of the South China Sea’s shipping lanes, 100 miles off the coast of China, — 200 miles from the Philippines to the south, 900 from Vietnam, less than 1000 from the Spratly Islands, and 700 miles from Japan’s home islands. Historically, Taiwan’s pivotal location off the China coast and between Northeast and Southeast Asia has served a variety of strategic purposes for regional powers, both offensive and defensive. In the contemporary era, Taiwan remains geographically at the intersection of most of East Asia’s danger points. Even a conflict on the Korean Peninsula could be affected by operations that might be launched from Taiwan.

When the Korean War broke out, President Harry Truman summed up Taiwan’s strategic significance in a few pithy words:

[T]he occupation of Formosa by Communist forces would be a direct threat to the security of the Pacific area and to the United States forces performing their lawful and necessary functions in that area.

Drawing on historical experience, the question is whether Taiwan would be as valuable a strategic asset to a potential aggressor in Asia today as it was for Japan in the 1940s. The only powers that presently threaten the peace and stability of the region are the Democratic People’s Republic of Korea in Northeast Asia and its patron and protector, the People’s Republic of China which has active ongoing disputes in both Northeast and Southeast Asia. Taiwan, which Beijing claims as an integral part of Chinese territory, would enhance China’s strategic position in both areas.

Controlling Taiwan would facilitate China’s operations in the South China Sea and enable it to assert its territorial and maritime claims even more aggressively against the Philippines, Vietnam, Malaysia, and Brunei. Suddenly, China’s sweeping “nine-dash line” would become even more real and more easily enforceable by Beijing. Those 1600 ballistic missiles now targeting Taiwan and the U.S. Navy could instead be moved to Taiwan itself and re-targeted against the ships and territories of other Southeast Asian states as well as the shipping lanes used by all the countries of the world. China would be in an enhanced advantageous position to make the South China Sea the “Chinese lake” it envisions.

China also sees Taiwan as one of the critical links in the so-called “first island chain” that includes Japan, the Ryukyu Islands, the Philippines, Malaysia, Indonesia, and Australia. Beijing sees the navigational “choke points” between those islands as constraining the People’s Liberation Army Navy’s access to the “second island chain” (Guam, the Marianas and some other small islands in the central Pacific) and from there into the open ocean far from China’s shores. Militarily, China’s East China Sea coast-line lacks deep-water ports to service its naval bases stationed there. Its submarines must operate on the surface until they are able to submerge and dive deep when they reach the area of the Ryukyu archipelagos.

If China controlled Taiwan, they would have a far easier exit from Taiwan’s deep-water ports into the Pacific. They could present a new threat to Japan–which is totally dependent on the East Asia sea-lanes for its energy and other raw materials. Chinese subs could also present an increased threat to the U.S. Seventh Fleet, Hawaii, and even the West Coast of the United States. Further, to the extent China’s far-ranging navy would embolden North Korea’s leaders and distract Washington and Tokyo, it could also directly endanger the security of South Korea.

So, from a purely naval and military perspective, control of the island of Taiwan would constitute a huge strategic asset for China and a threat to the region in both Southeast and Northeast Asia as well as to the United States. Such control over Taiwan, its technologically-advanced economy, and the entrance to the South China Sea would have major economic, diplomatic, and political implications for the region. There would likely be a cascading effect as governments recalculate their self-interests in the face of an even more powerfully situated China. If Taiwan were to fall under China’s control, Singapore might well be intimidated into a more pro-China position, consolidating Beijing’s control of the South China Sea with Taiwan in the north and Singapore in the south.

Denying China that asset and that leverage is clearly in the strategic security and economic interests of the countries of Southeast Asia, Japan, and the United States. Announcing the U.S. “pivot to Asia” before the Australian parliament in 2011, President Obama linked America’s strategic interests to the success of democracy in the region, committing “every element of American power” to achieving “security, prosperity, and dignity for all.” The Taiwan Relations Act confirms America’s commitment to Taiwan by stating that any existential threat to Taiwan would constitute “a threat to the peace and security of the Western Pacific area and of grave concern to the United States.” Any scenario in which Taiwan would be placed under Chinese control would mean that the US did not or could not intervene for either a lack of capability or, more likely, a lack of will. That, in turn, would mean the entire collapse of American credibility in the region and its diminishment globally. Taiwan is a moral and strategic asset that must and will be protected.

Jospeh Bosco served as China country director in the office of the secretary of defense, 2005-2006, and previously taught a graduate seminar on U.S.-China relations at Georgetown’s School of Foreign Service.  He is a fellow at the Institute for Taiwanese-American Studies (ITAS) and at the Institute for Corean-American Studies (ICAS). Image credit: CC by NASA/Flickr.