How many US jobs depend on easy border crossings?

How many US jobs depend on easy border crossings to and from Canada? This article estimates that 350,000 New York State jobs (and what about other states) would be at risk if pasports were required for all border crossings. A quote:

"Almost 350,000 New York jobs are supported by U.S.-Canada trade," Tom Minnick, the Council's lobbyist specializing in transportation issues, said in testimony delivered at a hearing sponsored by the U.S. Departments of State and Homeland Security. "Both Canadian and U.S. businesses have scores of cross-border operations operating almost seamlessly. This must be enhanced and encouraged." He added: "Any federal actions affecting the border must enhance and support this continuing business integration, not discourage it."

Minnick testified on a proposed regulation under the Intelligence Reform and Terrorism Prevention Act of 2004 that would require people crossing borders to carry passports or other special documentation for even routine border crossings.