Although relations between China and Taiwan have steadily improved in recent years, with the two countries signing a free-trade agreement this summer, for instance, America’s support for what Beijing continues to regard as a renegade province is still likeliest to cause a future confrontation between the two great powers.

Tensions became evident again last January when the United States approved a $1 billion arms sale to Taiwan that was heavily criticized in China. In the whole of the South China Sea region, China and the United States clash repeatedly. With concern about China’s naval ambitions mounting both in Washington and the region, supremacy over the Strait of Taiwan will likely be more hotly contested in the years ahead.

The geography of Chinese power is in part to blame. As Robert Kaplan explained last April, China feels “boxed in” from the east where it faces a chain of nations, from South Korea to Japan to Taiwan to the Philippines to Indonesia to Australia, that tend to oppose its increasing assertiveness in East Asia. In order to address this perceived threat from the high seas, Beijing is preparing to envelop Taiwan “not just militarily but economically and socially,” wrote Kaplan. He warned against the United States abandoning Taiwan which would leave other American allies in the Pacific “to doubt the strength of Washington’s commitments,” leading them straight into China’s arms. China’s growing military power however, combined with restraints that are both strategic and budgetary, on America’s part, may leave it with little choice.

In its comprehensive study, A Question of Balance, the RAND Corporation warns that an imbalance has developed across the Strait of Taiwan during the past ten years or so. The Chinese, with combined missile and airstrikes, are now quite capable of obliterating the Taiwanese air defenses within a matter of days. Indeed, the Republic of China Air Force (ROCAF) “does not appear operationally survivable in the first few days of a cross-strait war,” the report notes, therefore, “the battle for control of the air over Taiwan must be considered in a new light.”

The United States wouldn’t be able to bring enough fighters to the battle to offset China’s quantitative superiority. It hasn’t enough fighter planes stationed nearby, on Taiwan and in Japan, nor could it dispatch enough aircraft carriers to the site in time to effectively repel an invasion. In short, “the United States and Taiwan can no longer be confident of winning the battle for the air in the air.”

In order to restore balance, RAND recommends either to disperse American fighters among a larger number of bases — which may offer “the dual advantage of forcing China to use more missiles to suppress land based combat operations and possibly forcing Beijing to attack bases in countries other than Japan, such as the Philippines and South Korea” — or seek to pose the same kind of threat to China’s air force bases as it presents to those on Taiwan and Okinawa, Japan. “Like the Chinese, the United States and Taiwan could seek to use survivable and accurate ballistic missiles to strike Chinese air bases, cutting runways, destroying aircraft parked in the open, and possibly attacking hardened shelters.”

The report estimates that some six hundred additional missiles would be required to take out all of China’s fighter bases across the Strait. Currently, however, neither the United States nor Taiwan fields a missile with the appropriate characteristics. The 1988 Intermediate-Range Nuclear Forces Treaty prohibits Washington from operating missiles with ranges between 500 and 5,500 kilometers. Besides the political implications of withdrawing from this agreement, developing and deploying hundreds of missiles of intermediate range would place a significant financial burden of the United States Defense Department at a time when it is trying to cut spending across the board.

Retaliating on such scale against China in the event of an attack upon Taiwan would further raise the specter of Chinese action against American military bases in Japan and Guam. It is difficult to tell whether Beijing currently perceives such attacks as “crossing an escalatory line” that could legitimize full retaliation from the United States. “Making clear to the Chinese, through declaratory policy and force development, our belief that any such attacks would represent crossing a very bright line in terms of permitting counterforce attacks on the Chinese homeland, may be important in shaping the escalatory dynamics of any crisis and to enhancing the overall deterrence situation on the Strait,” notes RAND.

Complicating the situation from an American policy perspective is the variety of options at Beijing’s disposal should it wish to move against Taiwan. Besides taking out Taiwan’s air force and defenses to clear the way for an amphibious invasion, which China is then able to undertake with minimal losses, it could consider a prolonged coercive bombardment of the island. Assuming that Taiwan’s supply of interceptors is adequate; that the mainland will eventually exhaust its inventory of missiles; and that Taiwan remains resolute, “this approach may prove unsuccessful.” China would either have to follow up with a heavy, sustained bombardment of the island’s military and economic infrastructure, intended to compel capitulation, or risk losing significant numbers of men and material in an invasion attempt.

The least violent approaches would involve cyber attacks on Taiwanese infrastructure and a quarantine of shipping flowing to and from the island. RAND does not consider this option in detail besides noting that its effectiveness ultimately rests on China’s ability to back it up militarily.

In the event China intends to invade, “immediate and effective American intervention could jeopardize China’s ability to rapidly defeat Taiwan’s defenses and open the way for Chinese troops quickly occupying the island.” The bombardment scenario, on the other hand, leaves Beijing with the opportunity “to wait and see how the United States respond before committing itself to fighting the superpower.” Lastly, by crippling the island’s defenses, China might hope for the United States to ultimately choose not to engage a powerful adversary in what would appear to be a lost cause.

There are several ways for Taiwan and the United States to shape conditions in a way that are more advantageous to both. A restructuring of Taiwan’s air defenses to “ride out” heavy strikes on its bases and infrastructure could complicate Chinese planning and reduce the leverage Beijing can derive from its missile force and growing fleet of modern bomber aircraft. “Regaining the initiative in the air may require that the United States and/or Taiwan field a new, expensive, and politically problematic suite of strike capabilities aimed at China’s own air base infrastructure.” This doesn’t seem likely though.

“Making clear to Beijing the consequences of attacking American bases and forces in East Asia in terms of counterstrikes on the Chinese mainland could enhance deterrence,” according to RAND. In this regard, it may be worth considering the Quadrilateral Initiative which Australia, India, Japan and the United States launched in May 2007 in Manilla. Both the Philippines and Vietnam have clearly expressed their desire for greater American engagement in Southeast Asia to counterbalance Chinese economic and military unilateralism. Making them part of a Pacific defensive alliance should be able to deter China though it risks further undermining the strategy of strategic reassurance that the United States have been pursuing.

Moreover, the geographical asymmetry (i.e., Taiwan being just a few hundred miles from China and America all across the Pacific), “combined with the limited array of forward basing options for American forces — and China’s growing ability to mount sustained and effective attacks on those forward bases — calls into question Washington’s ability to credibly serve as guarantor of Taiwan’s security in the long run.” Indeed, it calls into question America’s ability to serve as guarantor of security in the whole of the Western Pacific.

American policymakers will have to determine whether the independence and security of Taiwan is sufficiently important to them “to rely not on a decreasingly credible conventional deterrent, but instead on the threat that any attack on Taiwan would risk a broader, more dangerous conflict between China and the United States.” If not, RAND stresses, “then where will Washington be willing to draw the line”? The Philippines? Korea? Japan? “With another decade of improvements in the [Chinese military] like what has been seen in the past ten years, these issues may become troubling indeed for the United States leadership.”

In conclusion, acknowledging that it is remains uncertain whether an “expansionist” China will ever arise, RAND recommends the United States and its allies “to pursue a strategy that simultaneously hedges against Chinese military might while engaging and enmeshing Beijing in a network of political, economic, and human ties that, in may be hoped, will eventually render that strength anachronistic.” If not, in the interest of “strategically reassuring” China, the United States may have to recognize East Asia as China’s exclusive sphere of interest, or at least contemplate sharing it.