Debate about America's borders is decidedly a one-sided affair. Rising illegal immigration and lingering worries about security have focused a bright light on the southern border. Left in the shadows is the northern border – a 4,000-mile stretch of land that's sparsely guarded even though it's twice as long as the US-Mexican border and sees far more international commerce. It's also much more varied.
The Ambassador Bridge in Detroit has all the high-tech capability of its southern counterparts – radioactive sensors, video surveillance, and cameras that capture license plate numbers. It handles, along with the Blue Water Bridge in Port Huron, Mich., 21,000 vehicles entering the United States every day. More than 60 percent of US-Canada trade passes through the Michigan border. Average time to cross: 14 minutes.
But in places like Derby Line, Vt., crossing the border is as easy as changing seats at the local opera house, visiting another section of the library, or, in some homes walking from one room to another. Residents embrace the border, even celebrate it as a way of life.
In Michigan and New York, the international border is defined by water. The US Coast Guard works alongside US Customs and Border Protection to patrol the line. But on Vermont's Lake Memphremagog, boaters face no screening. The customs and immigration station in Newport, Vt., is a phone booth, which foreign visitors are supposed to use to call border authorities when they arrive.
An estimated 90 percent of Canadians live within 100 miles of the border; many cross it regularly. Last year, they made 22.3 million one-day car trips to the US, says Statistics Canada. A prime magnet: New York's Niagara region, especially Niagara Falls.
Mutual trust has long characterized the US-Canadian line. New pressures threaten to change that.
• Next part: A long thin line. For expanded coverage, visit www.csmonitor.com/border.