GLENDIVE, Mont. — The final days of rancorous public debate over a $7 billion oil pipeline that would snake from Canada through the midsection of the United States have taken on an unexpected urgency this week, as the economic and environmental stakes of the massive project snap into focus at a time of festering anxiety about the nation’s future.

The round of public hearings by the State Department — stretching along the proposed pipeline route from a community college gymnasium here on Tuesday in eastern Montana, through Nebraska and Oklahoma to the Texas Gulf Coast — is ostensibly meant to focus on a single question: Is the pipe in the national interest?

Addressing that question, though — especially in the sprawling sweep of six huge states through which the pipeline or its pump stations would run like a spine — takes in a universe of conflicting, interlocking issues, from short-term economics to global climate, from the discontent of a rural belt losing population to issues of national energy security, joblessness, corporate power and prices at the corner pump.