WASHINGTON (Reuters) - President Joe Biden heads to South America on Thursday for a curtain call with global leaders after over 50 years in U.S. politics, but the man he tried and failed to keep from returning to power is likely to be the focus of many meetings: incoming U.S. President Donald Trump.

Biden will hold private meetings with Chinese President Xi Jinping and the heads of Japan, South Korea and Brazil during the summits of the Asia-Pacific Economic Cooperation, or APEC, in Peru and the Group of 20 leading economies, or G20, in Brazil. The meetings over six days are not expected to yield any major new agreements, senior Biden administration officials said, even as they are likely to touch on trade, security and global alliances.

"The APEC and G20 will be about one thing ... and that is Donald Trump - and what to expect from the next Trump administration on trade, alliances, and other issues," said Victor Cha, president of the Geopolitics and Foreign Policy Department at the Center for Strategic and International Studies.

Trump defeated Vice President Kamala Harris, the Democratic candidate, in the Nov. 5 presidential election after promising Americans he would impose steep tariffs on all imports, with higher ones aimed at Chinese goods, and signaled much softer support for Ukraine in its war against Russia. Harris' loss came after Biden was forced to step aside in the race because of concerns that at 81 he was too old for another term.

Trump's Republican party also won control of both houses of the U.S. Congress, giving him additional power to push through measures on trade and other issues.

Biden came into office in 2020 seeking to rebuild alliances strained during Trump's first term and tried to show that the U.S. remained engaged beyond its borders. He strengthened and expanded NATO and worked to counter China in the Indo-Pacific by building up multilateral alliances in Asia.

Trump has a fundamentally different world view than Biden, preferring bilateral meetings where he can practice transactional diplomacy over multilateral partnerships like NATO.

National security adviser Jake Sullivan told reporters on Wednesday that Biden will use the trip to say that America cherishes and invests in its alliances and thank those who have helped deal with an array of global problems.

"It's a message of principle. It's a message of practicality, and it's been one of the causes of President Biden's life," he said.

SWAN SONG OR LAME DUCK

Biden will meet with President Xi on Saturday during the APEC summit in Lima, White House officials said. The one-on-one meeting will be Biden's final opportunity to challenge the Chinese leader directly on its threats against Taiwan, alleged human rights violations and support for Russia's invasion of Ukraine.

It will be the first time the two leaders have met in person since a summit between the pair in California a year ago. That marked a turning point for U.S.-China relations after Biden's decision in early 2023 to shoot down a Chinese spy balloon that drifted over the United States increased tensions.

U.S. economic and military competition with China will define what the world looks like over the next 30 years, Sullivan said, adding that Republicans and Democrats have long demonstrated bipartisanship in the area of foreign policy.

Trump's incoming cabinet is stacked with politicians who have pushed a tough-on-China message.

Biden would not pass any messages to Xi from Trump, Sullivan said, but will likely speak about the necessity of avoiding a military conflict.

"He will also really reinforce the point that in order for us to manage this competition responsibly going forward, we have to sustain over the long term the channels of communication at every level, particularly the military to military level," Sullivan said.

Biden and Trump met for two hours at the White House on Wednesday.

Biden is also expected to hold a trilateral meeting with Japan Prime Minister Shigeru Ishiba and South Korean President Yoon Suk Yeol, and meet with Brazilian President Luiz Inacio Lula da Silva.

Erin Murphy, deputy director at the Center for Strategic and International Studies, said it will not be a swan song for Biden, but a different kind of bird.

"Not only is he a lame duck, but a super lame duck because his successor is going to have very different policies than he is," Murphy said.