Trump’s absence is also likely to fuel concerns among Asian leaders who want the US to push back against China’s increasing economic and military might.

Trump administration officials have been promoting a new “Indo-Pacific” strategy to bolster its commitment to the fast-growing region, after Trump withdrew from the Trans-Pacific Partnership trade deal and questioned the cost of security alliances with Japan and South Korea.

“His absence would doubtlessly solidify the impression that America has essentially abandoned its traditional presence in the Asia-Pacific, not to mention the non-starter Indo-Pacific,” said Oh Ei Sun, senior adviser for international affairs at the Asian Strategy and Leadership Institute in Kuala Lumpur.

Without Trump, Xi will have more space to advocate Chinese trade and development projects, such as his ambitious Belt and Road Initiative. Xi was the first leader to confirm his attendance to the Apec meeting in Port Moresby, Papua New Guinea, where he also plans to host his own summit with Pacific leaders.

Although US leaders have attended the events in recent years, missing them is not unprecedented.

In 2007, then US President George W. Bush drew flak for rescheduling a planned meeting with Asean leaders in Singapore. Former President Barack Obama, whose administration announced a pivot in military and diplomatic resources to Asia, skipped Apec in 2013 to handle a government shutdown.

Newly installed Australian Prime Minister Scott Morrison told reporters during a trip to Jakarta on Saturday that Trump’s decision to tend to matters at home was understandable, adding that Pence “speaks with the authority of the president.” The Singaporean Ministry of Foreign Affairs welcomed Pence’s visit to to the Southeast Asian city-state, noting in a statement that it would be his first as vice-president.

The Asian summits come days after midterm Congressional elections, which may determine Trump’s ability to withstand investigations into Russian campaign interference and election-season payments to alleged mistresses.

While Democratic leaders have largely avoided talking about impeaching Trump, Republican losses in the House or the Senate would greatly increase the risk of congressional action.

Trump plans to visit Paris on November 11 for a commemoration of the armistice ending first world war, White House Press Secretary Sarah Huckabee Sanders said in a statement.

During his trip to South America to attend the Group of 20 meeting, he will also travel to Colombia, she said.

After the US withdrawal from the TPP, trade ministers from the 11 remaining participant nations – Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam – signed a new agreement in Chile on March 8.

Collin Koh Swee Lean, a research fellow at the S. Rajaratnam School of International Studies in Singapore, said recent efforts by American officials in the region should help offset Trump’s absence.

Secretary of State Michael Pompeo announced US$300 million in regional security funding at an Asean meeting earlier this month and the US military is currently among nine nations taking part annual Southeast Asia Cooperation and Training exercises in Singapore.

“The US will still be regarded and expected to remain committed and engaged with the region and there’ll still be significant efforts of regional countries to keep the US presence in the region as the China shadow looms in the background,” Koh said.