(CNN) If China were to seize one of Taiwan's outlying islands, the US would have few good options to respond without risking a major escalation and a war between the superpowers, according to the conclusions from a recent war game conducted by foreign policy and defense experts.
The scenario, outlined in a report from the Center for a New American Security, began with China using military force to take control of Dongsha, a tiny atoll in the South China Sea between Taiwan and Hong Kong, where approximately 500 Taiwanese troops are stationed.
This type of limited aggression could be a precursor to the seizure of other islands near Taiwan or an outright invasion of the democratically governed island as Beijing seeks to test and prod Washington's resolve to defend Taiwan.
But once China has established its own military footprint on Dongsha and removed the Taiwanese troops, the US had no credible way to compel China to return the island to the control of Taipei, the report states. Economic sanctions took too long to produce effects and appeared too weak to influence China's decision-making, while any military action risked an escalation to war, which both the US and Taiwan want to avoid if possible.
Instead, the report stressed the need for a multilateral approach, suggesting the US, Taiwan, Japan and others work to deter China from seizing the island in the first place.
"The United States and Taiwan must begin coordinating today to build a credible deterrent against limited Chinese aggression or coercion toward Taiwan," the authors wrote. In every scenario, cooperation with Japan was critical to establishing an effective deterrent.
Beijing has ramped up military pressure on the island in recent weeks and Taiwan's defense minister earlier this month made a dire prediction: by 2025, China will be able to mount a "full-scale" invasion of Taiwan. The war game focused on an invasion of Dongsha in 2025.
Last week, US President Joe Biden stated that the US was committed to coming to Taiwan's defense if it comes under attack from China -- remarks that seemed in opposition to America's stated policy of "strategic ambiguity."
Asked twice during a CNN town hall whether the US would protect Taiwan if China attacked, Biden said it would.
"Yes, we have a commitment to do that," he said.
A White House official attempted to clarify Biden's comments on Taiwan after the town hall, saying the President was "not announcing any change in our policy and there is no change in our policy" in his remarks about China and Taiwan.
The US provides Taiwan defensive weapons but has remained intentionally ambiguous on whether it would intervene militarily in the event of a Chinese attack. Under the "One China" Policy, the US acknowledges China's claim of sovereignty over Taiwan.
But the issue is a major focus for the administration and China's plans for Taiwan are among the "preeminent issues" for the CIA's new China Mission Center, a newly-created body focused exclusively on gathering and analyzing intelligence on Beijing, CIA Deputy Director David Cohen said at an intelligence conference this week.
Intelligence officials have not yet seen anything to suggest that China is preparing a military invasion, according to people familiar with the assessments.
Cohen, speaking virtually to a conference in Sea Island, Georgia, said agency analysts are trying "to understand precisely how [Chinese president] Xi Jinping, who is fundamentally the decision maker on this issue, how he is thinking about Taiwan," both "in relation to the [20th Chinese Communist Party Congress]" in 2022 and "in relation to the comparative strength of Chinese military and US military."
The goal is to provide policy makers with "indicators" for a possible invasion — the factors that are driving Chinese decision-making — so US policymakers can determine the best course of action.
"There's a series of number-one issues with China," Cohen said. "Taiwan is definitely one of the number one issues with China we are focused on."
Former intelligence officials also speaking at The Cipher Brief conference suggested that an abrupt military takeover of Taiwan was unlikely, but that China would more likely follow the model used by Russia in its 2014 annexation of Crimea: a slow-rolling, undercover takeover at first followed by more overt military movements to solidify the reality on the ground.
Xi has also "undoubtedly concluded it is to his advantage when he decides to move on to Taiwan to coordinate those activities with Russians to complicate the United States problem with dealing with multiple crises," said Mark Kelton, a former CIA deputy director.
"Taiwan is going to be a test," said Norm Roule, former National Intelligence Manager on Iran. "Our resolve on China on Taiwan should be in question. People should say, 'If you didn't stand for Afghanistan, will you stand for other countries?'"
China has shown a broad willingness to test that resolve. Within the last few weeks, China has been sending record numbers of military aircraft into Taiwan's air defense identification zone (ADIZ), including fighter jets and early warning aircraft. The incursions did not violate Taiwan's airspace, which extends 12 nautical miles from the coast, but signaled a clear message about Beijing's intent.
"With the daily incursions into the air identification zone surrounding Taiwan, Xi is clearly signaling and testing Western resolve," said the CIA's former Deputy Director for Counterintelligence, Mark Kelton, at the conference.
On Tuesday, Secretary of State Antony Blinken called for Taiwan's "meaningful participation" in the United Nations, hailing the island as a "democratic success story." Even though Taiwan could participate as something less than a full member state, any such move to recognize Taipei would anger Beijing, which has made clear it views Taiwan as part of China.
"The fact that Taiwan participated robustly in certain UN specialized agencies for the vast majority of the past 50 years is evidence of the value the international community places in Taiwan's contributions. Recently, however, Taiwan has not been permitted to contribute to UN efforts," he said in a statement.
China's strenuous objections have kept Taiwan out of international organizations such as the World Health Organization (WHO). The US has maintained a policy of strategic ambiguity on Taiwan, declining to recognize the island's independence while also refusing to recognize Chinese sovereignty over Taiwan.
"Taiwan's exclusion undermines the important work of the UN and its related bodies, all of which stand to benefit greatly from its contributions," Blinken said.