For almost four decades, the United States has upheld its commitment to help Taiwan provide for its own self-defense against China — but the Trump administration has yet to affirm it. As a planned arms-sales package lingers in limbo, officials, lawmakers and experts worry that President Trump may be granting yet another unreciprocated concession to Beijing.

The relatively small sale to Taiwan — worth just more than $1 billion — was set to go in late 2016, but the Obama administration never pulled the trigger. After some early pro-Taiwan signals from President Trump, including a phone call with its president, most Taiwan watchers expected the new administration to move the package forward quickly. Now, administration and congressional officials say, the deal is stalled due to a lack of administration consensus and the fear that angering Beijing could complicate Trump’s top Asia priority: solving the North Korean crisis.

Those inside the government and on Capitol Hill who favor the sale say the administration risks giving in to China on one of its top priorities in exchange for nothing concrete, while putting the safety of the island democracy in increased danger.

“I think it’s important we keep our commitments under the Taiwan Relations Act and under Ronald Reagan’s ‘Six Assurances,’ ” House Foreign Affairs Committee Chairman Edward R. Royce (R-Calif.) told me. “This helps keep the peace and stability in the Taiwan Strait.”

The 1979 law to which Royce referred states that U.S. policy will be to “provide Taiwan with arms of a defensive character,” and Reagan’s 1982 “assurances” made clear that there was no end date for U.S. arms sales to Taiwan and that the United States is not required to consult with Beijing on the issue. These two documents have been the bedrock of bipartisan U.S. strategy on Taiwan ever since.

Following the successful summit between Trump and Chinese President Xi Jinping last month, many expected the administration to quickly approve the still-pending package and notify Congress. Now, administration and congressional officials say the White House has not provided clear policy direction to the national-security agencies or Congress, causing significant confusion.

Adding to those concerns were the president’s comments last month that he would consult with Xi before speaking again with the Taiwanese president. Trump said he would not want to be “causing difficulty” for Xi while seeking his help with North Korea.

One possibility is that the administration is preparing to bundle the limited Obama Taiwan arms package with more robust weapons. The Taiwanese government is expressing interest, for example, in acquiring the F-35 Joint Strike Fighter. But doing so might complicate the surrounding diplomacy even more and cause further delays.

Some U.S. officials want Trump to move forward with the smaller arms package now, to establish that the United States is still committed to aiding Taiwan’s defenses in the Trump era. Many are advocating for a return to a more regular process whereby requests are considered and sales notified on an annual basis.

“This is the only way to avoid the speed bumps of the U.S.-China relationship stalling arms packages for years on end,” one U.S. defense official said. The State Department said it does not comment on pending arms sales. The White House did not respond to requests for comment.

No matter which route the Trump administration takes, congressional support is assured. “I will strongly support any arms package the Trump administration will put forward for our friend and ally, Taiwan,” said Sen. Cory Gardner (R-Colo.), who chairs the Senate Foreign Relations subcommittee on East Asia.

Gardner was one of seven senators who visited Taiwan last year and pressed President Tsai Ing-wen to increase Taiwan’s own defense spending to 3 percent of its gross domestic product. Lawmakers worry that U.S. calls for Taiwan to spend more on defense will ring hollow if Washington won’t sell Taiwan the defense items it needs.

Even if Tsai reaches her goal, Taiwan cannot keep pace with Beijing. Taiwan will spend about $11.6 billion on defense this year, compared with $146 billion spent by the Chinese government, according to official figures. The Pentagon’s 2016 report on China’s military states that the nation’s “primary emphasis” is to develop capabilities for a potential conflict with Taiwan.

China must be reminded that it cannot push the United States away from its commitments to partners in the region with vague promises of help on North Korea that may never come. If China really does believe that helping to solve that crisis is in its interest, no Taiwan arms package will change that.

The Trump administration must resist the temptation to sacrifice long-term objectives for short-term aspirations. There will always be some imperative with Beijing that seems more urgent. But as Reagan well understood, the U.S. commitment to Taiwan’s defense is too important to deal away.

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