You wouldn't normally look to a Canadian election for a glimpse of the possible future of American politics. But maybe this is one time we should make an exception.

On Tuesday, the citizens of Toronto elected a new mayor. The successful candidate, Rob Ford, is a figure straight out of the U.S. Tea Party movement: a budget-cutting populist from a midpriced suburban neighborhood who speaks plain English and doesn't worry about his weight.

But there's one difference between Ford and any American Tea Party counterpart: In a city that is half foreign-born, Ford apparently swept the immigrant vote. A poll conducted by the Canadian firm Ekos the week before the election found foreign-born voters supporting Ford over a much more liberal opponent 52–30. Here's how Canada's National Post reported on Robert Ford's victory party: "Turbaned Sikhs partied with Chinese families. Black and white children chased each other around the tables. Jews, Muslims, and Christians cheered and applauded Mr. Ford's speech. The whole diorama seemed like something out of a public-service advertisement for diversity — except it was all real."

How did Ford do it? It's mostly what he did not do.

He did not exclude.

That may sound like an easy formula to follow, but what is easily said is not so easily done. During this election season, individual Republicans and conservatives have again and again stumbled into inter-group provocations. Think of Sharron Angle's ads about immigration as a threat to white schoolchildren; Ken Buck's comparisons of homosexuality to alcoholism; Newt Gingrich's endorsement of a description of the president as a "Kenyan anti-colonialist"; and Rush Limbaugh's endless references to "Imam Obama."

Ethnocentric messaging has imbued this election with much of its passion and excitement. In a contest where we can expect about 37 percent of the country to show up — and that 37 percent will be disproportionately drawn from the older and whiter portion of the population — these themes pack a lot of power.

They will also leave behind a lot of memories.

Every election continues a long-term process of brand definition. In fact, the Tea Party can itself be understood as an exercise in branding: "That Bush guy? He's not us. The housing bubble and financial crisis? Not our fault. TARP and bailouts and deficits? We're against them."

But branding can also be done unintentionally. Oldsmobile never intended to create an image as "your father's Oldsmobile." Things just added up that way. The Republican Party does not want to send a message: Not white? Go away. It works hard to recruit diverse candidates — and this year may have impressive success electing Latino Republicans, South Asian Republicans, Vietnamese-American Republicans, even some African-American Republicans. Bravo to those good souls who took the courageous step of running for office — and to the supporters who have done the hard work of campaigning for them.

An ever-more diverse roster of candidates is a great party achievement. But the hard work of many people can be undone by one candidate for Senate who makes it clear that he thinks the Civil Rights Act of 1964 was a big mistake, or by a national political figure who makes it clear that her definition of "real Americans" excludes most of the people who actually live in America.

The English have a wonderful saying: The test of a gentleman is that he never gives offense unintentionally. It's a good test too for a party concerned for its long-term future.