The war in Ukraine has exposes “serious deficiencies” in the U.S. defense industrial base that threatens to hinder the military’s power in a possible war with China, a study said.

Russia’s invasion of Ukraine almost a year ago pushed the United States to provide more than $27 billion in supplies that include everything from bullets to advanced missile systems. The military aid from the United States and its allies has helped to turn the tide of the biggest war in Europe in 80 years.

The continued fighting also has shown how quickly the United States can deplete its weapons inventories while lacking capacity to rebuild them quickly, according to the study by the Center for Strategic and International Studies, a think tank in Washington.

The U.S. defense industry is “currently operating at a tempo better suited to a peacetime environment,” according to the report, which was written by Seth Jones. “In a major regional conflict—such as a war with China in the Taiwan Strait—the U.S. use of munitions would likely exceed the current stockpiles of the U.S. Department of Defense, leading to a problem of ‘empty bins.’”

The war in Ukraine is mostly conventional in that it’s being fought with heavy machinery such as tanks and missiles. The differs from the more police-like presence in countries such as Iraq and Afghanistan after the 9/11 attacks. Any conflict with China likely would rely on inventories of U.S. military equipment.

The U.S. government needs to change its contracting procedures and restructure its weapons procurement to be more effective at deterring a conflict, according to the report. It recommends ways to improve the Department of Defense’s efforts to handle a protracted conflict.

“The good news is that there appears to be a great awakening in some areas of the Pentagon and Congress about challenges with the U.S. defense industrial base and the lack of preparedness for the wartime environment that now exists,” according to the report. “The ongoing war in Ukraine and escalating tension with China—including in the Taiwan Strait—highlight that the United States is no longer in a peacetime environment.”