David A. Andelman, visiting scholar at the Center on National Security at Fordham Law School and director of its Red Lines Project, is a contributor to CNN and columnist for USA Today. Author of " A Shattered Peace: Versailles 1919 and the Price We Pay Today, " he formerly was a foreign correspondent for The New York Times and CBS News in Asia and Europe. Follow him on Twitter @DavidAndelman. The views expressed in this commentary are his own.

(CNN) Donald Trump is poised to stick a second thumb in the eye of China and its newly ordained President for life, Xi Jinping. On Thursday, it was $50 billion worth of ill-advised tariffs against a country fully able to retaliate with a devastating tariff war of its own. Last week, the first thumb was in the form of a simple two-line note from the White House. Sandwiched between three congressional bills renaming post offices, Trump signed into law the Taiwan Travel Act, which encourages "visits between officials of the United States and Taiwan at all levels."

Basically, the bill allows the President of Taiwan and other top government officials, who for four decades have been barred from visiting the United States, to come for official visits and allows senior Americans to go there as well.

If the tariff regime is very much top of mind from Wall Street to Shanghai, the Taiwan Travel Act went little noticed in Washington, while looming large in Beijing, where leaders were bordering on the apoplectic. From the podium of the National People's Congress that had just given him the right to serve as President for life, Xi proclaimed angrily: "Any actions or tricks to separate the country are bound to fail. They will receive the condemnation of the people and the punishment of history." And he continued to affirm his country's unflinching intent of maintaining a one-China policy.

For decades this policy has met with tacit acceptance by Taiwan and the United States -- certainly since 1979 when President Jimmy Carter established full diplomatic relations with Beijing. At that moment, an act of Congress established guidelines for relations between the two countries, restricting any top-level visits by leaders of Taiwan and the United States.

But when the island's new President, Tsai Ing-wen, took office last year, she effectively repudiated the two-China concept, suddenly ratcheting up the temperature between Taiwan and the mainland. So now, in the wake of the new travel act, the waiting game begins on both sides of the Taiwan Strait: When might Tsai pay a visit to Washington with all that would entail?

Together with the $50 billion in tariffs Trump is prepared to levy on Chinese products and intellectual property, the President is reaching dangerously close to two of the existential third rails of dealing with China.

Indeed, two senior Taiwanese officials could scarcely contain themselves at lunch with me earlier this week in describing the Taiwan Travel Act as one step -- but a big one -- on the road toward containing a determinedly nationalist China. "The burden of maintaining peace and stability should not be placed solely on Taiwan, while ignoring the fact that Beijing also has the responsibility," said Brian Su, deputy director-general of the Taipei Economic and Cultural Office in New York.

"President Tsai has been cautious in dealing with cross-strait relations and has been calling for cross-strait dialogue since she took office. Still, Beijing refuses to resume talks with Taiwan, and continues threatening Taiwan by flying warplanes close to Taiwan's airspace, among other provocations."

China has shrugged off objections , considering such exercises part of its "military modernization program."

Trump's use of Taiwan as a red flag in the face of a China he has alternately wooed and stung, began even before his inauguration. In December 2016, in an apparently carefully choreographed move, Trump, as President-elect, took a congratulatory call from Tsai, the first direct communication between American and Taiwanese leaders since 1979.

One of those advocating strongly for the call and for a more muscular stance against China and for Taiwan was Peter Navarro, now the presidential adviser who is seen today as one of the principal architects of the massive new tariffs targeting China.

In a November 2016 article in Foreign Policy magazine, Navarro and co-author Alexander Gray wrote : "The Obama administration's treatment of Taiwan has been ... egregious. This beacon of democracy in Asia is perhaps the most militarily vulnerable U.S. partner anywhere in the world. As far back as 2010, the U.S. Defense Intelligence Agency warned that the balance of power in the skies above the Taiwan Strait was shifting toward Beijing."

Taiwan officials point out that not far away, in the South China Sea, China is actively building a string of fortified islands that could be used to interdict critical international shipping lanes. Taiwan imports the vast bulk of its oil supplies by ship in these very waters. And this week, on the day after Xi issued his thinly veiled warning to the United States and Taiwan, China sent its lone aircraft carrier group through the Taiwan Strait that separates the island from the mainland.

For China, despite its vast disparity in size and population, Taiwan looms as very much an existential issue. Recognizing an iota of its freedom and independence would give renewed encouragement to centrifugal forces among any number of people and regions on the fringes of what is still very much a conglomeration of republics. From Tibet to Inner Mongolia, there are non-Chinese ethnic minorities lusting for greater freedom, if not independence from Beijing -- and who pay close attention to developments along the Taiwan front and watch whether the mainland is prepared to give an inch.

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So, if Trump wants to clamp down, hard, on Chinese exports to the United States, he must recognize that the stakes will only be higher if closer American ties to Taiwan are stirred into this toxic broth. With Trump preparing his own overture to North Korea with the help of South Korea, he may feel he no longer needs Chinese intervention to contain the North's nuclear ambitions. He would be dangerously wrong.

Now, more than ever, China is very much a player, across the entire region. And Trump would be wise not to let the hotter heads of his administration, anxious to confront a China that will hardly shrink from defending its own most profound interests, steer America's course in a tense and dangerous region.