At Summit, U.S., Canada and Mexico Will Address Migration

For its part, the Biden administration has accused the Canadian government of practices that favor Canadian dairy farmers and raised concerns that Mexico’s energy policies give an unfair advantage to state-owned companies. Administration officials said on Wednesday that Mr. Biden planned to reaffirm U.S.M.C.A. provisions in support of labor rights protection, a reference to a dispute settled against Mexico earlier this year.

Officials expect agreements to be reached over vaccine sharing. Leaders in Canada and Mexico will agree to share “millions” of doses with poorer countries in Latin America and the Caribbean, an official said. The three countries will sign onto a pact to reduce methane emissions in the oil and gas industries by as much as 75 percent by 2030, and form a working group to address supply chain issues.

The more delicate discussions will come with Mr. López Obrador. Mexico, long an underdog in the relationship with its neighbors, has earned considerable leverage in a year that saw a wave of pandemic-fueled migration from Latin America. Mr. Biden has had to rely ever more on Mexico to keep the flow of people from overwhelming the southwestern border, and to house tens of thousands of migrants who might otherwise head north.

For Biden officials, the importance of maintaining strong Mexican enforcement was made clear in September, when thousands of Haitians walked across the border to Texas.

“The power balance between the Mexican government and the U.S. government has shifted because of the circumstances,” said Duncan Wood, the vice president of strategy at the Wilson Center. Mexican officials, Mr. Wood said, “know they can hurt the Biden administration, and they know that the Biden administration knows that.”

Mr. Biden’s dependence on Mexico has put the fate of a key piece of his domestic agenda in the hands of Mr. López Obrador, who has lashed out at the United States and pursed policies that run counter to American interests.

Mr. López Obrador’s government has sought to jail university professors, gutted funding for civic organizations, attacked journalists by name at national news conferences and championed a constitutional reform that would ensure the dominance of the state-owned electricity giant in Mexico’s energy market.