President Biden and his associates came to office with extensive experience in transatlantic affairs. But over the past four years, they have also focused on the Pacific, where China is striving to be the dominant player. Their main effort: construction alliances stand up to China.

President-elect Donald J. Trump has already signaled a different approach to China. He invited Xi Jinping, the Chinese leader, at his inauguration on Monday. The two spoke by phone on Friday, and Mr. Xi sends China’s Vice President, Han Zheng, at the ceremony, breaking the Chinese tradition of having the ambassador in Washington attend.

In contrast, the recent activities of the Biden administration directed towards China. Mr. Biden held a call last Sunday with the leaders of Japan and the Philippines to cement the new tripartite security arrangement he helped build it. Secretary of State Antony J. Blinken visited South Korea and Japan this month on his last official trip.

According to Mr. Biden and his associates, they Mr. They give Trump a sharp competitive advantage over China, the United States’ biggest rival.

Of all Mr. Biden’s foreign policies, historians may ultimately see his approach to China as existing in continuity. His administration built its own structure on the foundations of the competition set up by Mr. Trump’s team and is now upending them.

It is unclear what Mr. Trump will do about it. He admires the autocratic Mr. Xi, and sees China mostly through the lens of economic negotiations. Trump’s billionaire advisers, including Elon Muskthey want to maintain and perhaps expand business relations with China.

But his the best picks because foreign policy aides are more closely related to Mr. Biden: They claim that the United States must contain China on many dimensions, using a range of security and economic tools.

One early test will be whether Mr. Trump to implement a ban on TikTok, a Chinese social media app popular among young Americans.

Mr. Biden signed bipartisan legislation last year to ban TikTok based on national security concerns unless its parent company, ByteDance, sells it to investors not tied to a “foreign adversary.” ByteDance still owns TikTok and the White House published on Friday that Mr. Trump will enact a ban. Mr Trump said on Saturday that he would probably give TikTok 90 days delay the ban, and the CEO of the company plans to attend his inauguration.

The policy of Mr. Trump’s move towards China in his first term was the introduction of tariffs on some Chinese products. Mr. Biden and his aides have kept them while expanding policy along three main lines: strengthening alliances and creating new security partnerships in the Asia-Pacific region; limiting technology exports to China; and the rapid initiation of industrial policy in the United States.

In short, Mr. Biden sought to turn China politics into global politics.

During Mr. Biden’s tenure, already strained relations soured when House Speaker Nancy Pelosi visited Taiwan, a de facto independent island that China claims as its territory, and Chinese spy balloon hovered over the United States. But his team struggled to restart high-level communications, including between the two armies.

The United States and China “are competing, obviously competing strongly, and yet there’s an element of stability to the relationship so we’re not on the edge of a downward spiral right now,” White House national security adviser Jake Sullivan said in an interview in a West Wing conference room.

“It’s a significant evolution over four years in the way the relationship is managed on both sides,” he added, using the acronym for the People’s Republic of China. The Chinese Communist Party, he said, has now accepted the Biden team’s framework of “managed competition” for the relationship.

He animated the Biden administration idea that China wants to displace the United States as a dominant world power, said Rush Doshi, the China director who previously served on the National Security Council during the Biden administration. Many Republican lawmakers and policymakers share that sentiment.

Coming into office, Mr. Biden and his aides saw huge gaps in critical areas, including the U.S. defense industrial base, Mr. Sullivan said.

The administration has set up two “big tent” policies, he said: investments aimed at rejuvenating American manufacturing, technological innovation and supply chains; and investment in alliances and partnerships, “so that we expand China’s strategy to truly be a regional and global strategy.”

Mr. Sullivan pointed to alliances not only in Asia, but also in Europe. The team of Mr. Biden helped convince European nations to drop some commercial deals with China and NATO to come out tougher on China and signal support for Taiwan.

China’s partnership with Russia during President Vladimir V. Putin’s all-out invasion of Ukraine helped nudge the Europeans in that direction, as did China’s cyberespionage efforts.

But transatlantic allies have not gone as far as the United States in viewing China as a threat. Some European politicians continue to prioritize trade relations with China, the world’s second-largest economy. And Mr. Trump antagonizing European nations could jeopardize the work of the Biden administration.

Moreover, America’s allies could run to China’s arms if Mr. Trump makes good on his threat to impose universal tariffs even on them.

Mr. Trump also says allies are taking advantage of the U.S. military and must pay the United States for protection or fend for themselves. In Asia, this thinking would apply to Japan, South Korea and the Philippines as well Taiwan.

The Biden administration took the opposite view. In creation a network of new security agreements among America’s allies in Asia, he has tried to make their militaries more intertwined with each other and with that of the United States — which, according to Mr. Biden’s team, would help deter China.

Mr. Biden also moved to strengthen military capacities several allies and the presence of the US military in Asia: sending Tomahawk missiles to Japan; working with Britain to equip Australia with nuclear submarine technology and the submarines themselves; and expanding US military access to Philippine bases near Taiwan.

In private conversations in Washington, Chinese officials complained that it was a policy of containment.

The central question, difficult to answer and relevant to Mr. Trump’s team, is whether the Biden administration has struck the right balance between deterrence and provocation. Is China speeding up its military build-up and becoming more aggressive in the region because of American moves in its backyard?

Beijing took notice when Mr. Biden said on four separate occasions that the U.S. military would defend Taiwan in the event of a Chinese invasion.

Jessica Chen Weiss, a professor at Johns Hopkins University who worked briefly at the State Department under Mr. Blinken, noted that the administration’s policies did not ignite the conflict, and that some of its diplomacy helped.

“It was possible to avoid extremes,” she said. “Whether the bungling was ambitious enough to stop the underlying tendencies remains to be seen.”

At the summit meetings Mr. Xi directly criticized the policy signed by Biden, which Chinese officials insist is part of a containment effort: export controls imposed on advanced semiconductor chips, including the kind needed to develop artificial intelligence.

After the payment of the first tranche in 2022. Sullivan described him as a policy of keeping “fundamental technologies” out of the hands of rivals by establishing a “small yard, high fence”.

Some experts argue that politics backfired and actually pushed China to accelerate innovation. And the less Chinese companies rely on American technology, the less leverage the United States has over China, they say.

Mr. Sullivan said the criticism “blames the chronology.”

“Our semiconductor export controls were really a reaction to China’s very openly, very systematically stated policy that they would indigenize their semiconductor manufacturing capacity,” he said.

Some former officials point to other shortcomings of the policy. Ryan Hass, director of China for President Barack Obama’s National Security Council, cited three: Mr. Biden and his team had no serious trade agenda for Asia, appeared timid in their dealings with China, and seemed more comfortable engaging with advanced democracies on China policy than with developing countries.

But overall, he said, the policy has worked: “America is in a stronger competitive position with China than it was when Biden took office.”