CANADA and Mexico share the fortune, or misfortune, of a border with the world’s most powerful country, which looks down on both of them. For 20 years, as privileged trading partners of the United States, they have had the opportunity to influence it by creating a shared vision for North America. Instead the two have bickered like rivals in a tawdry ménage a trois.

Canada plays the part of the wronged partner. It has jealously sought to protect the relationship with its neighbour, fearing that Mexico may steal its thunder. “Canada is quick to give offence and Mexico is quick to take it,” says Laura Dawson, author of a report on the bilateral relations for the Canadian Council of Chief Executives, a business group. That could be shrugged off as irrelevant in a region where the only bond that matters is with the United States. But there are economic costs for North America as a whole, including the United States, because more could be done to link supply chains and energy markets trilaterally rather than just bilaterally.

Canada was a reluctant participant in the negotiations for the North American Free Trade Agreement (NAFTA), which was launched in 1994. It agreed to join largely to safeguard the advantages it had won from a prior free-trade deal with the United States. After the terrorist attacks on September 11th 2001, efforts to strengthen NAFTA through trilateral negotiations lost momentum. Instead, the United States, Canada and Mexico have sought to tackle border and security issues bilaterally.

Relations between Canada and Mexico have become more brittle this year; the leaders of both countries have pointedly snubbed each other. Visas are the cause of much of the ill will. President Enrique Peña Nieto cancelled a visit to Canada in June, after the government of Stephen Harper refused to lift a “temporary” visa requirement imposed in 2009 following a sharp rise in Mexican asylum requests. Mexico feels demeaned: it used to enjoy visa-free status in Canada, which is rare for a Latin American country. “President Peña would not subject himself to the horrors of having to present a visa,” says his ambassador in Ottawa, Francisco Suárez Dávila.

Mr Peña had hoped that a meeting with Mr Harper earlier this year, on the sidelines of the “three amigos” summit with President Barack Obama, would lead to a breakthrough on the issue. But Mr Harper publicly refused to budge, saying visas were a sovereign matter and not for negotiation.

Mexican experts say the visa issue represents more than just wounded pride. They acknowledge that Mr Harper’s government originally responded to a rise in spurious asylum claims at a time of soaring crime in Mexico. But the situation has improved since and they are irked by the unwillingness to discuss the issue even though business and tourism between Mexico and Canada have been affected.

Business groups in both countries are keen to see warmer ties. Although trade between the two countries under NAFTA has grown almost sevenfold, most of it is linked to the United States, and two-way investment is modest. There is potential to develop supply-chain linkages of the sort that now criss-cross the border between Mexico, the United States and Canada, but only a few Canadian companies—such as Bombardier, an aerospace and rail firm—have taken the plunge.

The most promising area for further integration of the three economies is energy, which could further strengthen North America’s competitiveness as a manufacturing hub. Mr Peña’s scrapped visit to Canada’s oil heartland, Calgary, was supposed to give him a chance to promote landmark reforms allowing private investment in the oil and gas industries for the first time in over 75 years.

On August 7th and 8th senior officials from both countries were due to meet in Mexico city to revive negotiations on the visa issue. A recent decision to expedite permits for seasoned travellers from Mexico to Canada was seen as a mildly positive step. Yet Mexican officials have little optimism that Mr Harper will scrap the requirement altogether. Many will quietly hope that the more Mexico-friendly Liberals will oust him from power in elections scheduled for October 2015.