During his New Year's address, Xi Jinping made clear that the self-governing island of Taiwan, viewed as a rogue province by Communist Party leadership, remains in Beijing's crosshairs. In countering China's ambitions, newly minted acting Defense Secretary Patrick Shanahan must recognize the domestic political reasoning behind Xi's speech. As the trade war drags on and China's economic growth continues to slide, Xi is looking to nationalism as an alternative to economic prosperity to bolster the Communist Party's political power and legitimacy.

In his speech, Xi signaled a growing interest in the longstanding goal of unification. "That the two sides of the strait are still not fully unified," he said, "is a wound to the Chinese nation left by history.”

To fix that perceived historical problem, Xi said, "We make no promise to abandon the use of force, and retain the option of taking all necessary measures.” He also warned that such force could be used against “intervention by external forces.”

While the CCP has continuously offered some version of this threat since coming to power in 1949, over the past year Beijing has grown increasingly aggressive. With live-fire drills on a Taiwan-sized piece of land and a brewing dispute over freedom of navigation in the South China Sea, as well as his latest speech demanding unification, China seems more willing and ready to take action on territorial interests.

That stance, of course, is aided by Beijing's growing international economic and political power. With loans and diplomatic sweet-talking, China has convinced various developing countries to cut ties with Taiwan. With threats to close off access to lucrative domestic industries, China has successfully pressured international firms to toe its line and, for example, list Taiwan as part of China on printed and electronic maps.

For the White House, and particularly for Shanahan, Beijing’s posturing boils down to a new challenge in his first days on the job — a challenge exacerbated by the Trump administration's inconsistent policies on China and Taiwan.

The Trump administration has made a point of backing Taiwan, the self-governing island claimed by China but effectively independent since World War II. Trump was the first president since 1979 to speak directly with the president of Taiwan, officially the Republic of China. His administration has approved $1.4 billion in arms sales and he has signed legislation promoting more official visits. Most recently, on the last day of 2018, Trump signed the Asia Reassurance Initiative Act that commits the U.S. "to counter efforts to change the status quo and to support peaceful resolution acceptable to both sides of the Taiwan Strait.”

But Trump has also embraced Chinese President Xi Jinping and, as he looks to make a deal to end the trade war, seems more willing to mix politics into an economic agreement. For Taiwan, the result is uncertainty about just where U.S. policy stands when it comes to supporting its democracy and independence.

Shanahan must recognize Xi's domestic political need of the increased focus on nationalism, manifested as territorial ambition against Taiwan. Any long-term plan, ideally coordinated with security and economic interests in mind, will be unlikely to succeed, should it threaten Xi's stability.