President Trump’s retrenchment of U.S. global leadership on issues such as free trade, climate change and multilateral alliances has opened the door for an unlikely rival to assert itself — China.

Since Trump’s unexpected victory in November, Chinese President Xi Jinping has moved to position his fast-developing nation as a defender of globalization, and he has accelerated Beijing’s challenge to U.S. primacy in Asia.

This budding shift of power dynamics has alarmed U.S. allies and partners in the region and raised the stakes as Trump prepares to welcome Xi for a two-day summit starting Thursday at his Mar-a-Lago estate in South Florida. The two are expected to discuss a wide range of issues, including North Korea’s mounting nuclear threat and a lopsided trade imbalance in China’s favor, in what aides called a meeting aimed at establishing a working relationship.

Administration officials told reporters Tuesday that Trump will exhort Xi about the “urgent” need to exert more economic pressure on Pyongyang to curb its nuclear and ballistic missile testing, as U.S. patience with North Korea has been exhausted after it turned down opportunities to join the “community of nations.”

“The clock has now run out, and all options are on the table for us,” one official said of North Korea.

(Jenny Starrs/The Washington Post)

In an interview last weekend with the Financial Times, Trump suggested he would consider using the threat of trade sanctions as leverage to persuade Beijing to act with regard to Pyongyang.

“If China is not going to solve the problem, we will,” the president said. Speaking to business leaders in Washington on Tuesday, Trump said he had “a lot of respect” for Xi, but he emphasized China must do more to open its markets to U.S. companies. “We have to do better,” Trump said.

More broadly, however, the Trump administration has not developed or publicly enunciated a coherent policy to deal with China’s growing economic and military clout. And Trump, who called China a currency manipulator during his campaign, has delivered mixed messages on how far he is willing to go to confront Beijing.

For example, Trump angered Chinese leaders by accepting a congratulatory phone call from Taiwan’s president after the election and questioning the United States’ commitment to the “one China” policy that has undergirded the bilateral relations for decades. But, after Xi reportedly gave him the silent treatment, Trump agreed to honor the policy during a phone call.

The summit comes as Trump’s administration has yet to fill leadership positions across government agencies, including the State Department and Pentagon, leading foreign policy analysts to fret that the Mar-a-Lago meeting is premature.

White House aides said the summit is intended as a more informal affair similar to Japanese Prime Minister Shinzo Abe’s visit to Mar-a-Lago in February, although Xi, unlike Abe, will have no session with Trump at the White House.

Xi also is not expected to play golf with Trump in Florida as Abe did. Rather, the two men, and their wives, will spend about 24 hours together, including a dinner Thursday and working lunch Friday, White House officials said.

President Trump and Chinese President Xi Jinping begin a two-day summit Thursday at Trump’s Mar-a-Lago estate in Palm Beach, Fla. (Paul J. Richards/Agence France-Presse via Getty Images)

“Since there’s no China policy we can discern, the question arises, ‘On what basis is the president going to enter this talk?’ Who the hell knows,” said Robert D. Blackwill, who served as U.S. ambassador to India during the George W. Bush administration.

In 2015, Blackwill co-authored a paper, widely read in Washington, calling for a new “grand strategy” aimed at containing China’s rise.

“It is very dangerous for presidents to be utterly extemporaneous in their interactions with major powers,” said Blackwill, now a senior fellow at the Council on Foreign Relations. “Contrast that with the Chinese. Do we think that Xi Jinping will come to the meeting with a very clear set of strategic objectives and strategies? Absolutely.”

Analysts said Xi, mindful of Trump’s campaign rhetoric, will seek to soothe his concerns and tout increased Chinese investment in the United States — a tactic also employed by Japan’s Abe.

At the same time, Xi is expected to pursue his strategy of establishing China as a worthy rival to the United States in Asia. The Chinese leader, who took office in 2012, has sought buy-in from the United States for what he calls “a new model of great power relations.” It is Xi’s concept for a system in which the two countries avoid conflict by agreeing not to meddle in each other’s “core interests.”

The Obama administration, after initially echoing the phrase, quickly reversed course as China moved to expand its influence through an Asia trade pact that excluded the United States, an infrastructure development bank for Asian nations and provocative maritime operations in the East China Sea and South China Sea.

Last month, however, Secretary of State Rex Tillerson raised eyebrows during a visit to Beijing when he appeared to endorse Xi’s vision by parroting some of the language used by Chinese leaders.

“What they’re likely to do is feed into the sense in the Trump administration that disengagement from the global system is a good thing,” said Michael Auslin, an author and Asia analyst at the conservative American Enterprise Institute. He added that Xi will “present Trump with a fait accompli that this is the new style of great power relations.”

Trump administration officials point to the president’s push for greater military spending as evidence he does not intend to shy away from confrontation. During the campaign, Trump denounced China’s maritime expansionism.

But the blustery unilateralism that has defined Trump’s “America first” agenda has already had consequences.

While President Barack Obama sought to hedge against China’s rise by building multilateral partnerships, Trump has moved to unwind them. In his first week, Trump signed an executive order pulling the United States out of the 12-nation Trans-Pacific Partnership that Obama touted as an alternative to the Chinese trade model.

Last week, Trump moved to reverse federal regulations established by Obama to curb U.S. carbon emissions, casting doubt on the United States’ ability to meet its obligations under a global climate agreement signed in Paris in 2015 that includes China.

Into the void stepped Xi, with a pair of speeches at an Asia-Pacific economic summit in Lima, Peru, last fall and at a forum of global economic elite in Davos, Switzerland, in January in which he offered a stout defense of liberalizing trade rules and taking steps on climate.

“In my view, economic globalization . . . delivers benefits to all,” Xi said in Lima. In Davos, he called the climate accord a “hard-won achievement” and added that “all signatories should stick to it in instead of walking away from it.”

Trump did not send a representative to Davos, which took place days before he was sworn in — aides said he viewed the gathering as a betrayal of his populist campaign message.

“I do not want to be the president of the world,” Trump said at an event hosted by building trade unions Tuesday.

While analysts said China also is not interested in, or capable of, assuming the mantle of global leadership, they emphasized that Beijing’s neighbors in Asia have been forced to rethink their relationships with the United States.

“There are big opportunities for the Chinese as a consequence of the America first policy,” said Ian Bremmer, president of the Eurasia Group, a global risk assessment firm. “A lot of countries that used to think they could count more on the United States and were already concerned under Obama are vastly more so under Trump.”