Air defense planners in Taiwan face a daunting challenge. They need to have enough capacity to deter China, which not only has a large military but, more importantly, for the past 25 years has spent heavily on modernizing that force. In modern warfare, air dominance is important in its own right, but it also enables other types of military operations by land and sea forces.

Thus an important capability for Taiwan is to be able to contest China's People's Liberation Army (PLA) air dominance. In the past, Taiwan's fighter aircraft have been the mainstay of their air defenses, and in the future these aircraft will command most of the air defense budget. But China has found ways to put those aircraft in check, making them an expensive luxury in Taiwan's defense budget.

Taiwan should begin to think beyond an air defense that relies so heavily on its fighter aircraft. Surface-to-air missiles (SAMs) would offer greater defensive capabilities and are a better investment moving forward.

China's investments pose a three-pronged threat to fighter aircraft, making Taiwan's aircraft vulnerable on the ground and outnumbered and outclassed in the air. On the ground they are vulnerable to a variety of attacks from ballistic, cruise missiles and other fixed-wing aircraft. China has invested in missiles that are accurate enough to target aircraft on the ground as well as in the runways they rely upon to sustain operations.

Although Taiwan may have some mountain hideaways to store the aircraft safely, those aircraft cannot be used to conduct sustained operations from mountain bunkers. Operating the aircraft from other nontraditional locations, like a highway strip, would not solve the problem because the PLA will have a number of ways to keep continuous track of aircraft in flight, note their landing location and quickly target those areas with a variety of weapons.

Taiwan's fighter aircraft are not only exposed on the ground, but once in the air they face a numerically superior adversary that has begun to field aircraft with capabilities that surpass all of Taiwan's fighters, which began operating in the 1990s. Taiwan is refurbishing its F-16 fleet with new radar and other upgrades, but even when the upgrades are complete they will still lag behind PLA aircraft

Local journalists look at a model of Tienkung III (Sky Bow III) missile (front) and a Hsiungfeng III missile (back) at The Chungshan Institute of Science and Technology in Lungtan district of Taoyuan city on December 2, 2014. The most advanced home-produced surface-to-air missiles can help defend Taiwan's airspace against Chinese attacks for up to 20 years, the arms project developer said. AFP PHOTO / SAM YEH (Photo credit should read SAM YEH/AFP/Getty Images)
Local journalists look at a model of Tienkung III (Sky Bow III) missile (front) and a Hsiungfeng III missile (back) at The Chungshan Institute of Science and Technology in Lungtan district of Taoyuan city on December 2, 2014. The most advanced home-produced surface-to-air missiles can help defend Taiwan's airspace against Chinese attacks for up to 20 years, the arms project developer said. AFP PHOTO / SAM YEH (Photo credit should read SAM YEH/AFP/Getty Images)

A model of a Tienkung III (Sky Bow III) missile, front, and a Hsiungfeng III missile are exhibited in Taoyuan, Taiwan, in 2014.

Photo Credit: Sam Yeh/AFP/Getty Images

Taiwan's fighters are too vulnerable to be able to play a decisive role if the PLA conducts large-scale attacks. Without other options for air defense, the PLA could easily gain air superiority. Starting with the 1991 Gulf War in Iraq, the United States showed how difficult it is for a ground force, in that case the Iraqi Army, to survive in the face of persistent precision air attacks while facing a competent ground force. For Taiwan, the inability to contest PLA air dominance has ripple effects. PLA air superiority could prevent most of Taiwan's defense forces from operating effectively. Taiwan needs localized relief from air attack for successful defensive operations.

PLA capabilities are forcing Taiwan to substantially restructure and rethink its air defenses. In the coming years, Taiwan's force of over 300 fighter aircraft will command a large fraction of its air defense budget, but because of the threats to fighter aircraft, whether on the ground or in the air, they can no longer be the mainstay of Taiwan's air defenses.

The question is: Could Taiwan make productive air defense investments to deter future attacks? SAMs are not a perfect solution, because they are not invulnerable either, but on balance they are more survivable than fighter aircraft on Taiwan and could provide a viable way to contest PLA air superiority, particularly if Taiwan uses its SAMs in a different way. SAMs cannot defend fixed targets in the face of a large missile inventory; all they can do is raise the price to attack. A more effective use of SAMs would be to help protect Taiwan's other defense forces from PLA air threats. If Taiwan's SAMs were used to support such operations, they could both cut losses and improve the effectiveness of these defense forces.

Taiwan's defense problem is challenging, but Taiwan will spend a considerable sum on air defense capabilities in the coming years, and those investments could be made much more effective. SAMs offer a way to maximize those investments and Taiwan should consider shifting a greater share of air defense spending to SAMs and away from fighter aircraft.

Michael J. Lostumbo is a senior international policy analyst at the Rand Corp.