Much has been made—rightly—of the weaknesses in the U.S. defense industrial base and the need to address those shortcomings. But the U.S. also faces a similar problem which is just as significant: the inability to mobilize its reserve forces en masse.

Essential to wartime planning is the ability to mobilize, if needed, reserve forces for active service in war—a tool that has proved useful to the U.S. since the Sept. 11 terrorist attacks.

Effective mobilization of reserve forces is key not only to supporting the operations of active-duty forces (which often require reserve support to operate) but to sustaining combat operations in a prolonged conflict.

But even though many mobilizations have occurred since Sept. 11, the U.S. has not conducted a full-scale, regionally-focused mobilization exercise since 1978. Thus, it’s not a stretch to say that the U.S. largely lacks the ability to quickly access, mobilize, and deploy reserve forces en masse for combat duty.

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In 1978, the U.S. military conducted two mobilization exercises: “Petite Nugget” and “Nifty Nugget.”

The first was a week-long initiative examining the industry’s ability to surge for war-time needs on an expedited timetable. The second was a three-week mobilization exercise involving 24 military commands and 30 civilian agencies focused on reinforcing combat units in Europe.

According to the official report, Petite Nugget quickly revealed that the industry could not “provide new equipment during the early months of a short-warning conflict,” that it was slow to respond to the needs of the Defense Department, and that “sizable expenditures would have to be obligated in peace-time to speed it up.”

The results of Nifty Nugget were also less than promising, indicating poor military readiness and inadequate sea and airlift capabilities.

Yet these negative results ultimately produced even greater investments in overall readiness: establishing registration for selective service, instituting biennial mobilization exercises, and investing in sea and airlift assets.

Today, as we face an increasing threat from China, a mass mobilization exercise could again prove useful in highlighting our military-readiness shortfalls and capability limitations.

By identifying weaknesses in mobilization, we can identify what spending is necessary to improve resiliency and what practices best improve overall readiness. We can also focus our attention specifically on the steps the U.S. would need to take to prepare for a wartime crisis in the Indo-Pacific region.

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In conducting this exercise, the U.S. could also simulate the effects of cyber-attacks and other mobilization-focused attacks, which would allow for a more real-world analysis of steps China might take in a conflict. At the same time, the U.S. could simulate a complete cessation of access to China’s economy, which would help us determine the effects of a full decoupling of both economies.

Further, we could test the ability of industry and support personnel to provide adequate assistance and supplies to deployed forces, as well as the military’s ability to tap into existing munitions magazines for sustained combat in the Indo-Pacific region.

Even as the Trump administration seeks a stable relationship with China, Beijing still pursues a confrontational and adversarial relationship with the United States. While effective deterrence can dissuade China from adopting an aggressive military posture, U.S. efforts at deterrence will be unconvincing if it lacks an effective war-winning strategy.

A broad, Indo-Pacific-focused mobilization exercise would be the first step toward establishing such a strategy. It would both dissuade China from its aggressive tendencies and test the mobilization resiliency of U.S. reserve forces—allowing us to identify gaps and address weaknesses.

It would also signal that if it comes to conflict, the U.S. is resolved both to fight and to win.