The ninth Summit of the Americas officially began Monday in Los Angeles, marking the first time the U.S. has hosted the meeting of North American, South American, Central American, and Caribbean leaders since the inaugural pan-American summit in 1994. 

The theme for this years’ summit is “Building a Sustainable, Resilient, and Equitable Future.” President Biden, who arrives at the summit on Wednesday, plans to focus on crafting a cooperative economic vision for the Americas, fighting climate change, tackling food insecurity, tightening supply chains, preparing for the next pandemic, and managing migration. But the summit’s agenda has so far been overshadowed by drama over its guest list.

Mexican President Andrés Manuel López Obrador confirmed Monday that he will not attend the summit, citing Biden’s decision not to invite Cuba, Venezuela, or Nicaragua. López Obrador has been the central figure in a push by mostly leftist leaders to get the three excluded nations re-invited, and the White House said his decision to send the Mexican foreign minister instead was not unexpected. But his snub could convince some leaders in Central America and the Caribbean to stay home as well.

“We do not believe that dictators should be invited,” White House Press Secretary Karine Jean-Pierre said Monday. She said at least 23 heads of government will attend the summit, “on par with what we’ve had in the past.” 

Only 17 of the region’s 35 leaders attended the last Summit of the Americas in Peru in 2018. Former President Donald Trump was among those who opted not to go, though his administration then offered in 2019 to host the next summit.

Analysts said the no-shows could undermine Biden’s goal of mending ties in a region neglected by recent administrations and increasingly open to overtures from China. 

“The region is in serious economic distress, and its economic struggles are eroding support for democracy,” Benjamin Gedan, head of the Wilson Center’s Latin America Program, tells Politico. “Biden’s election generated high expectations for U.S. reengagement in the region, and so far, most everyone has been disappointed.” It’s not too late to fix that, added former U.S. envoy Bernard Aronson, “but if you look at what Biden’s got on the plate elsewhere — an administration can only do two or three big things at a time. He’s got Ukraine, Iran, China, inflation. I don’t think he has a lot of bandwidth available given what’s on his plate.”