A Chinese attack on Taiwan could trigger a war involving two million Chinese troops, half a million Taiwanese troops and the combined fleets and air forces of the United States and Japan.
It would be the “ultra-mega,” to borrow a phrase from Ian Easton, an analyst with the Virginia-based Project 2049 Institute.
China has some key advantages going into this possible ultra-mega war. Compared to China, Taiwan is tiny, less wealthy on a national level and isolated. China can mass its best troops, ships and planes along a short geographic front and attack at the time of its choosing. The Chinese People’s Liberation Army Rocket Force has aimed thousands of missiles at the closest American and Japanese bases. To intervene, U.S. and Japanese forces must fight their way through these missiles as well as the PLA Navy’s submarines.
But Taiwan can win, according to the Center for Strategic and International Studies in Washington, D.C. CSIS recently ran a series of war games simulating a Chinese invasion of Taiwan in 2026 and varying degrees of U.S. and Japanese intervention. “In most scenarios, the United States/Taiwan/Japan defeated a conventional amphibious invasion by China and maintained an autonomous Taiwan,” CSIS analysts Mark Cancian, Matthew Cancian and Eric Heginbotham explained in their summary of the war games.
One weapon in particular was decisive in the scenarios where Taiwan and its allies prevailed: the American Joint Air-to-Surface Standoff Missile, a stealthy, air-launched cruise missile that’s compatible with an array of USAF and USN warplanes.
Specifically, it was the extended-range JASSM-ER that helped to win the war, by sinking most of the Chinese fleet over the course of two bloody weeks starting with the first Chinese rocket barrage on Taiwanese bases.
“The JASSM … is a special case,” the Cancians and Heginbotham wrote. “Its long-range precision guidance and stealthy characteristics make it an important munition for the United States.”
The reasons for the JASSM’s importance are obvious. A war over Taiwan begins and ends at sea. First, a Chinese transport fleet—combining scores of navy amphibious ships and potentially hundreds of civilian vessels—must cross the hundred-mile-wide Taiwan Strait and land Chinese troops on Taiwanese beaches or offload them at whatever ports Chinese special forces can capture in the early hours of the conflict.
While fighting rages in Taiwanese towns and cities and along its strategic mountain highways, a powerful American-Japanese naval force should—assuming U.S. and Japanese leaders make good on their promises to defend Taiwan—assemble then sail toward the embattled island country, aiming to cut the PLA’s supply lines and restore the Taiwanese military’s own supply.
Any weapon that can blunt the Chinese landing and safeguard the later U.S.-Japanese intervention is a potential war-winner. As the CSIS analysts ran, modified and reran their simulation, 24 times with different assumptions baked in, they quickly learned that JASSM was that war-winning weapon. In the iterations of the game where Taiwan and its allies won the war, “the JASSM had a decisive impact on outcomes.”
In CSIS’s “base scenario”—seemingly the most likely one—tens of thousands of people died on both sides of an intensive, two-week war. The Taiwanese air force and navy blinked out of existence amid powerful Chinese rocket barrages. The Americans lost two aircraft carriers, several other warships and submarines and nearly 300 aircraft.
But China’s losses were far greater, and more important to the war’s outcome. Nearly 140 Chinese ships sank to the bottom of the Pacific Ocean, including most of the transport ships hauling and supplying the invasion force. While American submarines accounted for many of the sinkings, it’s the bombers—USAF B-1s, B-2s and B-52s armed with JASSM-ERs and flying from bases well outside the range of Chinese missiles—that inflicted the most destruction.
This is exactly what USAF planners and Lockheed Martin had in mind when they conceived of, developed and deployed the JASSM, and later the JASSM-ER, starting in the late 1990s. The original JASSM—with its 1,000-pound warhead, GPS and inertial navigation and infrared seeker—entered USAF service in 2003. The 14-foot, subsonic JASSM ranges just 230 miles, but its stealthy shape helps it to avoid detection and interception.
Despite some hiccups in development, JASSM is an effective weapon. But it’s the JASSM-ER that U.S. forces are counting on to win a war with China. By lightening the missile’s frame and rearranging its components to make more room for fuel, Lockheed doubled its range without adding much to its $1.3-million unit cost.
JASSM-ER debuted in 2018. The USAF is buying the new missiles as quickly as Lockheed can make them. CSIS projected the service would have more than 3,600 JASSM-ERs in 2026, the year in which its Taiwan war games were set.
That’s enough missiles not only to sink a lot of Chinese warships, but also to bombard Chinese ports and air bases and further degrade the PLA’s logistics. “With each squadron of 12 bombers carrying around 200 stealthy, standoff [cruise missiles], the United States could rapidly cripple the Chinese fleet and leave the invasion force stranded,” the Cancians and Heginbotham wrote.
But lest anyone in Washington, Tokyo or Taipei prematurely declare victory over Beijing, CSIS’s analysts pointed out one huge uncertainty. It’s unclear just how well JASSM-ER works at sea. Lockheed optimized it for overland strikes, after all. The missile’s infrared seeker expects the contrast and clutter you typically see over dry ground.
Yes, the Pentagon is developing a version of the original JASSM—the Long-Range Anti-Ship Missiles—with a seeker and warhead optimized for hitting and sinking ships. But this maritime JASSM is too early in its production runs to make a big difference in any near-term conflict. CSIS projected the USAF and USN would have just 450 LRASMs in 2026.
If war breaks out soon, American bombers mostly will launch JASSM-ERs. Taiwan will be counting on those missiles working against ships.
The CSIS team expressed confidence. It noted a recent USN budget document discussing the merging of the software code in the LRASM and JASSM-ER. This effort could erase the targeting distinction between the two weapons and result in what budgeteers described as “a merged Navy JASSM baseline” where the JASSM is equally capable of striking targets on land or at sea.
It’s hard to overstate the importance of this one change in a war over Taiwan. “In games where the JASSM-ER has maritime strike capabilities, the abundance of U.S. munitions made U.S. strategy an almost uncomplicated exercise,” the CSIS experts wrote.