YOU can usually count on diplomats to be, well, diplomatic in their public utterances, reserving blunter statements for meetings behind closed doors. Not so Francisco Suárez Dávila, Mexico’s ambassador to Canada, who earlier this month said his country’s relations with Canada were stagnant and that Canada held an Anglo-centric view of the world in which Mexico does not exist. His message does not augur well for the official visit to Mexico by Stephen Harper, Canada’s prime minister, which begins today, or for the meeting of all three North American leaders at a NAFTA summit two days later in Toluca (pictured), the capital of Mexico State. The immediate cause of Mexico’s anger is Canada’s refusal to lift a visa requirement for all visitors from Mexico imposed in 2009 to stem a surge in false-refugee claims. Although the number of false claimants has dropped (along with business and tourist visits), the requirement remains in place, leaving Mexico in the company of countries such as Algeria, Iraq and Kyrgyzstan. Neither lobbying by the Mexican government nor a call from the group representing Canada’s largest companies have swayed the Canadian government. Speculation that Mr Harper is just waiting for the Toluca summit to make an announcement has been rebutted by government officials.

The rancour between two of North America’s three amigos, as the leaders of Canada, Mexico and the United States were once called, predates the visa problem. Canada was a reluctant signatory to the North America Free Trade Agreement, joining to protect access to the American market it secured in a 1989 Canada-US deal rather than out of any desire for closer relations with Mexico. The two have been rivals for US affection and attention ever since.

This suits the United States, which prefers the bilateral approach when it comes to trade. Michael Wilson, Canada’s trade minister when NAFTA was negotiated and later a Canadian ambassador to Washington, says that the US has shown little interest in taking a joint approach to trade policy with Canada and Mexico and is negotiating tariff reductions bilaterally in negotiations for the proposed Trans-Pacific Partnership.

Mr Harper’s disinterest in Mexico—this week’s visit is his first in eight years as prime minister—is mirrored by public attitudes. In a 2011 survey of attitudes towards Latin America, 48% of respondents had an unfavourable view of Mexico, shaped by media coverage of drug-related crime, corruption and illegal immigration to the US. Only 16% of those surveyed thought Mexico was vitally important to Canada, compared with 70% for the US.

Yet Canada needs to diversify its trade from the United States, which absorbed 75% of Canadian goods exports in 2012, and Mexico, as a member of NAFTA, would seem to be one of the easier foreign markets to penetrate. Although bilateral goods trade with Mexico has risen more than sixfold since NAFTA took effect in 1994, it started from a low base and only reached C$31 billion ($28 billion) in 2012. Canada-US bilateral trade that same year was just over $600 billion. Recent liberalisation measures by the government of Enrique Peña Nieto are likely to open up more opportunities for trade and investment, especially in Mexico's energy sector. Exploring those opportunities may not be harmed by frosty relations at the top, but they cannot be helped.

Just before Mr Harper left for Mexico his office put out a press release saying “Mexico and Canada enjoy excellent bilateral relations”. The Mexican ambassador described relations as having entered post-NAFTA old age “with flaws, limitations and increasing wrinkles”. One of them is misreading the situation.