As President Bush and Mexican President Vicente Fox, together with Canadian Prime Minister Stephen Harper, wrapped up their two-day summit in this Caribbean resort town, deeper cooperation on trade, energy, security, and immigration were all promised.
But what's really ahead for US-Mexico relations is not completely clear.
The tenor of the bilateral ties will certainly depend on the sort of immigration bill US lawmakers adopt in the months ahead. But future relations may also depend on another factor, or rather, another actor: Andrés Manuel López Obrador. The leftist leader of the Democratic Revolutionary Party (PRD) has consistently polled ahead of his rivals over the last year and is expected to win July 2 presidential elections here when Fox, constitutionally, must step down.
A former mayor of Mexico City who endeared himself to many with folksy speeches, handouts to the poor, and big public works projects - and a person sometimes compared to Venezuelan President Hugo Chávez - Obrador is a frequent critic of various aspects of current Mexico-US ties. If elected, he would add to the growing number of leftist leaders in Latin America.
Claudio Gonzalez, president of the Center for Economic Studies of the Private Sector calls Obrador "a retrograde and dinosaur-like leftist" who would spook investors and threaten the nation's hard-won economic stability and close relations with the US. "If populism returns ... Mexico could be left friendless and in bankruptcy."
Laura Carlsen, Director of the Americas Program at the International Relations Center, a left-leaning civic-advocacy group based in Mexico City, says that US-Mexico ties might get a bit more complicated, but not necessarily worse. "There will no doubt be points of disagreement along the line between López Obrador and Bush," she says, "... but a lot of Mexicans would actually like to see a president who stands up to the US a little more - and I don't think the Bush administration is afraid of that either."
Obrador has come out against many of the free-trade economic policies supported by the US. Just as the North American Free Trade Agreement (NAFTA) enters the final years of its 15-year phase-in period, with the last agricultural tariffs to be lifted in 2008, Obrador talks of reopening chapters of NAFTA that he says have hurt Mexican corn and bean farmers.
On foreign policy, Obrador has reiterated his support for Mexico's long-standing nonintervention and pacifist policies, and made digs at what he sees as Fox's "mirroring" of US foreign policy, especially regarding Cuba. "We're not going to meddle in the internal life of other peoples and other governments, because we don't want them meddling in ours," Obrador said at a late February rally in Mexico City. "The next president of Mexico is not going to be the puppet of any foreign government."
And, on the question of illegal Mexican immigration to the US, Obrador talks particularly tough. He has, for instance, proposed taking a much more proactive role than Fox by using Mexico's 45 consulates in the US as "prosecutorial" offices to "protect our countrymen from mistreatment, discrimination, and the violation of their human rights." And he has stridently criticized Fox for being an elitist too eager to please the US.
"It's infuriating to see how President Fox, because he is dedicated to maintaining economic policies that only benefit the elite, does not have the moral or political authority to confront the disgrace of a wall on the border," Obrador told supporters at a January rally in Mexico City, in reference to a bill passed by the US Congress in December that would see a fence built along a third of the US-Mexico border. Fox has voiced stringent opposition to the barrier, but Obrador argues that for someone who has staked his presidency on immigration, Fox has far too little to show for his efforts.
Fox's conservative, pro-business National Action Party (PAN) has, on its part, tried to frighten voters, and policymakers in Washington, by painting Obrador as a Chávez-like leader who will harm relations with the US.
Last month the PAN began airing a TV ad showing a clip from a diplomatic flap in which Chávez warned Fox last year: "Don't mess with me, sir. You'll get stung." The ad then cuts to video of Obrador yelling at Fox: "Shut up, citizen president," and concludes with a voice intoning: "Say no to intolerance."
At home, neither the advertisement nor unsubstantiated rumors that Chávez is financially helping Obrador's campaign have done much to erode Obrador's lead over PAN candidate Felipe Calderón, his nearest rival. Roberto Madrazo, the candidate for the long-dominant Institutional Revolutionary Party is running third in polls.
Ms. Carlsen points to Brazil's center-left President Luiz Inacio Lula da Silva as an example of how Obrador would lead. "[Lula] came from a far more explicitly leftist party and background and his relationship with the US government has been surprisingly close." Obrador, she says, is "far from a flaming radical, despite the right-wing PAN party's attempts lately to compare him to Hugo Chávez. In fact, you could hardly imagine two leaders with more different styles."
Obrador himself says he has never met, or even spoken over the phone, to Chávez - and has called attempts to tie them together "desperate."
Michael Shifter, vice president of the Inter-American Dialogue, a Washington think tank, says Obrador, unlike Chávez, has focused on national questions and has for the most part avoided direct attacks on the US. "But still," points out Shifter, "the concern is that, given the deep connections between the US and Mexico, any comment or gesture from Obrador that might be considered offensive towards the US could touch a nerve center in Washington and provoke a strong reaction."
In the meantime, Bush avoids speculating on how relations might be changed. "I am obviously aware that there is a political season coming up," he told reporters in Washington as he set off for the Cancún summit, "... but until someone is sworn in office, my relationship will be with Vicente Fox as the leader of our important friend to the south."
• Ms. Harman is Latin America correspondent for the Monitor and USA Today.