Bonjour, America!

Watching the free-for-all in Washington over immigration reform, it’s easy to conclude that an airtight border has always been our national goal.

After all, the unmistakable message behind the bevy of border-security measures in the immigration bill, which was approved last month by the Senate and now sits in the House, is that a country that can’t prevent foreigners from swarming unchecked across the land border is in serious jeopardy.

The trouble with this narrative, as I discovered when serving as the American consul general in Quebec City in the late 1990s, is that it flies in the face of our own history.

From the late 1800s to the early 1900s, nearly a million French Canadians poured across our northern border to take jobs in New England textile and shoe mills. This movement, part of an even larger mass of Anglo Canadians also moving south, surged after the Civil War and ended with the Great Depression, with peaks in the 1880s and 1920s.

The majority of these job seekers — French speaking, slow to assimilate, mainly Catholic — entered without visas, work permits or passports, because during most of this period our land border with Canada was effectively wide open.

The United States not only survived this unregulated onslaught, it prospered. Indeed, our history suggests that having an open border with our continental neighbors isn’t such a bad thing.

Exactly how many French Canadians made the trek is difficult to calculate, because before 1895 no federal immigration officials monitored the northern land border. Neither Canada nor the United States had seen the free movement of people across their common border as a problem seeking a solution.

Even when the United States finally built land border posts in the late 1800s and early 1900s, they were aimed primarily at Eastern and Southern Europeans who were using Canada to sidestep immigration screenings at seaports like New York and Boston.

Canadian migrants, despite their huge numbers — by 1900 the number of Canadian-born United States residents equaled an astounding 22 percent of Canada’s entire population — continued to receive special treatment.

They did not have to pay the head tax imposed on other foreigners, and no records were kept of their entry until the Naturalization Act of 1906. And it wasn’t until 1926 that they had to get a visa to move permanently to the United States.

When the United States first imposed immigration quotas in 1921, Canadians — along with Mexicans and other Latin Americans — were exempt, a status they enjoyed until the quota system was modified in 1965.

So how did the United States fare during this period of largely unregulated border crossings? And what happened to all those French Canadians, whose linguistic and religious differences made them stand out more sharply than Anglo-Canadian migrants?

Most flocked to mill towns in New England, where they powered the textile factories that boomed after the Civil War. In a pattern that reflects today’s Mexican migration, they followed family members to places where jobs were plentiful, but hard and undesirable.

Their labor was in such demand that mill owners sent recruiters to Quebec to hire more. Entire villages would relocate south, usually by train, swelling the populations of towns like Biddeford, Me.; Southbridge, Mass.; and Woonsocket, R.I., whose populations by 1900 were more than 60 percent French Canadian.

As with Mexican migrants today, not everyone welcomed this influx. One Massachusetts official called French Canadians “the Chinese of the eastern states” in an 1881 report that described them as “indefatigable workers” who had no interest in assimilating and drove American wages down. They were even vilified at home in Quebec, where religious and political leaders sent emissaries to woo them back.

Some did return, but the majority stayed and assimilated. Besides helping to fuel New England’s manufacturing boom, thousands served in the world wars. Rene Gagnon, whose Quebec-born mother worked at a shoe factory in Manchester, N.H., was one of the Marines photographed raising the American flag over Iwo Jima in 1945. The author Jack Kerouac was born of French Canadian parents in Lowell, Mass.

Far from causing the collapse of the republic, these largely unregulated border crossers helped build the United States we know today.

What the French Canadian experience shows is that our current obsession with border security is inconsistent with our history, undermines our economic vitality and is likely to fail.

Instead of vainly trying to fortify our land borders, we should be working with Canada and Mexico to keep the things we should really worry about — terrorists, weapons of mass destruction, cocaine — out of North America all together.

Stephen R. Kelly,visiting professor of the practice of public policy, is a retired American diplomat and the associate director of the Center for Canadian Studies at Duke University.This commentary was originally published in The New York Times.