We are already seeing signs that Latin America may unite in condemning the United States if President-elect Donald Trump goes ahead with his plans to build a border wall, deport millions of undocumented immigrants, dismantle or renegotiate free-trade deals with Mexico and other countries, and overturn the U.S. normalization with Cuba.

Last week, while on a trip to Chile, I already saw some signs that the reaction to Trump’s plans will not come only from the usual suspects — the anti-American autocrats who rule in Venezuela, Ecuador, Bolivia, Nicaragua and Cuba — but also from U.S. allies. Trump’s negative agenda for the region risks antagonizing the entire hemisphere.

Former Chilean President Ricardo Lagos, a leader of Chile’s ruling party and a top contender for the 2017 elections, is already calling for a Latin American summit to denounce Trump’s proposed border wall if the U.S. president-elect goes ahead with his plan to dramatically expand the existing fence.

“If the proposal to build a wall on the U.S-Mexican border materializes, I propose that we lead a Latin American summit to fight its implementation and protest against it, because it affects us all,” Lagos wrote in the daily El Mercurio. “We must say with strength and clarity that, under these circumstances, we are all Mexicans.”

Lagos, a moderate politician who has always denounced anti-American populists, added that Latin Americans should also team up to defend the 2015 Paris climate change accords, which Trump criticized during the campaign.

Meanwhile, the foreign ministers of Guatemala, Honduras, El Salvador and Mexico met Nov. 21 to map out a joint strategy to confront possible mass deportations by a Trump administration.

“For Central America, Trump’s immigration ideas are a very serious problem,” Mexico’s former foreign minister Jorge Castañeda told me. “They (Central American leaders) want to talk with Mexico because there is a convergence of interests.”

Central America would be especially vulnerable to massive U.S. deportations because the region depends heavily on family remittances from its migrants in the United States. In addition, Central American economies would have a hard time absorbing a massive influx of deportees.

Peru’s President Pedro Pablo Kuczynski, a former U.S. citizen, told the Russia Today news agency on Nov. 11 that “we will oppose by all avenues, including the United Nations,” Trump’s idea to build a border wall.

Kuzcynski had told me in a September interview that Trump’s idea of building a border wall was “unfortunate,” and that demanding that Mexico pay for it was “scandalous.” When I asked him whether he was worried about a Trump victory, he said, “no doubt it’s a cause of concern, especially because of the idea of protectionism, of breaking free-trade agreements that have been good for all sides.”

Trump has vowed to renegotiate or withdraw from the NAFTA free-trade deal with Mexico and Canada and says he will kill the Trans Pacific Partnership trade agreement between the United States and 11 Asian and Latin American countries, including Peru.

My opinion: I still hold some hope — maybe it’s just wishful thinking — that Trump will significantly scale down his plans for the border wall, massive deportations and economic isolationism once he gets to the White House.

While every country has the right to deport foreign criminals, the idea of expelling millions of hard-working people who pay taxes is cheap populism, which will hurt rather than help Americans.

If Trump goes ahead with his negative agenda, he will be giving ammunition to Latin America’s beleaguered leftist populist leaders. And he will force pro-American leaders in the region to distance themselves from Washington, whether it’s because they sincerely oppose Trump’s policies or because they will not dare to go against the massive anti-Trump sentiment in their own countries.

In either case, if Trump wants to make some friends in this hemisphere, he needs to come up with a positive agenda. If all he has to offer is building a wall, mass deportations and scrapping free-trade deals, much of the region is likely to shift from polite disagreement to strong diplomatic opposition. That would be bad for all sides.

— Andres Oppenheimer is a Latin America correspondent for the Miami Herald.