President Donald Trump announced on Saturday that he planned to pull out of the Intermediate-Range Nuclear Forces Treaty, known as INF, claiming that Russia had violated the agreement.
While the treaty remains in place, China is free to develop and deploy increasingly sophisticated land-based missiles, including those designed to target US aircraft carriers patrolling the Western Pacific.
A former Pentagon official, Dan Blumenthal, said pulling out of the treaty would allow the US to field easier-to-hide, road-mobile conventional missiles in places like Guam and Japan.
This would make it more difficult for China to strike against US ships and bases in the region as it would need to spend more on missile defences, forcing the country into a costly arms race.
“It will change the picture fundamentally,” Mr Blumenthal said.
While Mr Trump has blamed Russian violations of the treaty for his decision, he also claims Beijing has been fielding new and more deadly missile forces.
These include China’s DF-26 intermediate-range ballistic missile (IRBM), which has a maximum range of 4,000 km (2,500 miles).
According to the Pentagon, this can threaten US land and sea-based forces as far away as the Pacific island of Guam. It was first fielded in 2016.
“If Russia is doing it [developing these missiles] and China is doing it and we’re adhering to the agreement, that’s unacceptable,” Mr Trump said on Sunday.
John Bolton, White House national security advisor, noted that recent Chinese statements suggest it wanted Washington to stay in the treaty.
“And that’s perfectly understandable. If I were Chinese, I would say the same thing,” he told the Echo Moskvy radio station. “Why not have the Americans bound, and the Chinese not bound?”
Kelly Magsamen, who helped draw up the Pentagon’s Asian policy under the Obama administration, warned that any new US policy guiding missile deployments in Asia would need to be carefully coordinated with allies, something that does not appear to have happened yet.
Mismanagement surrounding a US treaty pullout could unsettle security in the Asia-Pacific, she warned.
“It’s potentially destabilising,” she said.
Experts warn that China would put pressure on countries in the region to refuse US requests to position missiles there.
Abraham Denmark, a former senior Pentagon official under Obama, said Guam, Japan and even Australia were possible locations for US missile deployments.
“But there are a lot of alliance questions that appear at first glance to be very tricky,” he cautioned.
US officials say Washington is right to focus on China’s missile threat.
Harry Harris, who led US military forces in the Pacific before becoming US ambassador to Seoul, said earlier this year that the US was at a disadvantage.
“We have no ground-based [missile] capability that can threaten China because of, among other things, our rigid adherence ... to the treaty,” Mr Harris told a Senate hearing in March, without calling for the treaty to be scrapped.
Asked about Mr Trump’s comments, China’s foreign ministry urged the US to “think thrice before acting”.
“Talking about China on the issue of unilaterally pulling out of the treaty is completely mistaken,” spokeswoman Hua Chunying said.