United States President Donald Trump has long blamed Mexico for the flow of Central Americans seeking to enter the United States’ southern border.

Migrants just cross Mexico like they’re “walking through Central Park,” Trump once claimed.

In truth, Mexico is aggressive in enforcing U.S. immigration policy. In 2014 President Enrique Peña Nieto implemented a robust deterrence effort, the Southern Border Program, to deter migration across Mexico’s border with Guatemala.

Between 2014 and 2015, Mexican deportations of Central Americans traveling to the U.S. – primarily Guatemalans, Hondurans and Salvadorans – more than doubled, from 78,733 in 2013 to 176,726 in 2015. During the same period, U.S. border agents detained half as many Central American migrants at the border.

That compliant attitude is about to change. Mexicans elect their next president – and 18,000 other elected officials, from mayors all the way up to senators – on Sunday, July 1. It is the biggest and most expensive election in Mexico’s history. And Trump’s draconian new immigration policies, which include detaining children and criminally prosecuting migrants, have taken center stage in the presidential race.

Mexico’s four presidential candidates argue over many issues, from corruption to the economy. But they all agree on this: Mexico can no longer maintain its policy of helping enforce U.S. immigration laws.

Nobody’s piñata

Presidential front-runner Andrés Manuel López Obrador is an outspoken Trump critic who recently denounced separating migrant families as “arrogant, racist and inhuman.”

He is widely expected to win on Sunday. The 64-year-old leftist has led the four-way race for months and currently has 49 percent of voter support, according to the latest polls.

López Obrador launched his presidential bid on April 1 with a rally in Ciudad Juárez, the northern Mexico city where thousands of migrants cross into the U.S. each year. In a fiery speech, López Obrador promised that, with him as president, Mexico would reassert itself as a “free, sovereign and independent” nation and would not be the “piñata” of any foreign power.

AP Photo/Andres Kudacki

An early critic of President Peña Nieto’s Southern Border Program, López Obrador has accused the Mexican government of committing human rights violations in its persecution and deportations of Central American migrants.

On his watch, Mexico would still “pay special attention” to its southern border, López Obrador says, but it would no longer do Trump’s “dirty work.” López Obrador wants Mexico to respect existing laws that protect the human rights of migrants and guarantee that asylum-seekers can find refuge in its borders.

Ricardo Anaya, the right-of-center second-place candidate, has also attacked President Peña Nieto’s policy of detaining and deporting Central American migrants. Anaya says his country must be a “moral authority” on immigration, treating Central Americans in Mexico as justly and humanely as Mexican immigrants would like to be treated in the U.S.

The changing face of migration

Illegal immigration to the U.S. has changed radically over the past two decades.

The number of Mexicans apprehended crossing illegally has plummeted, from more than 1.6 million in 2000 to 130,000 last year.

Central Americans, driven by endemic violence and pervasive poverty, now make up a bulk of all people caught trying to cross the U.S.-Mexico border. In 2017, U.S. Border Patrol agents there arrested 303,916 migrants. Just over half of them – 162,891 people – were from Guatemala, Honduras and El Salvador.

Mexico has thus become a major transit country for migrants.

It is also, increasingly, their final destination. Mexico saw 12,700 asylum requests from Central American refugees, up from 8,800 in 2016 and 3,400 in 2015. Only the U.S. received more Central American asylum-seekers, according to the United Nations Refugee Agency.

Rather than welcome Central Americans, President Peña Nieto’s administration in 2014 accepted US$90 million of American funding to better secure its borders. His government has ruthlessly persecuted migrants who journey through the country.

Mexico detained 40,920 Central American migrants between January and April 2018 alone. Nearly 35,000 were deported.

In 2016, the Obama administration recognized Mexico for “absorbing” so many Central American migrants. Trump has expressed no such gratitude.

AP Photo/Alexandre Meneghini

The high cost of appeasing Trump

In 2016, Peña Nieto’s advisers invited both U.S. presidential candidates to visit Mexico.

Clinton declined the invitation. Trump, whose 2016 campaign was fueled by promises to build a “big, fat, beautiful” border wall, accepted.

In a joint press conference on Aug. 31, 2016, Peña Nieto emphasized his country’s contribution to U.S. immigration enforcement. The border, Peña Nieto said, represents a “shared challenge” and a “great humanitarian crisis.”

AP Photo/Dario Lopez-Mills

Trump was subdued at that event. But he ridiculed the Mexican president at a campaign rally later the same day, insisting that Mexico would indeed pay for a border wall.

“They don’t know it yet,” he told supporters in Phoenix, Arizona, “but they’re going to pay for it.”

Peña Nieto never recovered from this diplomatic disaster. According to the newspaper El Universal, 88 percent of Mexican citizens were offended by Trump’s visit – and by Peña Nieto’s polite, submissive behavior. The Mexican president’s approval rating plunged to below 25 percent and never bounced back.

His party has paid the price. José Antonio Meade, the presidential candidate for Peña Nieto’s Revolutionary Institutional Party, has been stuck in third place throughout the 2018 election season.

Another Mexican revolution

López Obrador, a savvy career politician, has benefited from Peña Nieto’s mistake.

Even the choice of location for his campaign launch, Ciudad Juárez, sent a powerful message that López Obrador’s attitude toward Trump would not be one of deference.

Juárez is not just a border city – it’s a symbolic place in Mexican history. It was the bulwark where Mexico’s only indigenous president, Benito Juárez, in 1867 fought back a French invasion and re-established a sovereign Mexican government. Juárez is also the city whose 1911 capture by pro-democracy forces during the Mexican Revolution forced dictator Porfirio Díaz to resign.

López Obrador closed his campaign on June 27, four days before the election as required by Mexican law. At a massive rally in Mexico City’s Azteca stadium, he promised 100,000 supporters that he would “transform” their country.

Like so many of López Obrador’s lofty campaign commitments, his immigration plan is short on details. But it’s clear Trump has already lost his power of intimidation south of the border – even if, to paraphrase his own verbal jab, he doesn’t know it yet.