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 being held along the pipeline’s proposed route — from a community college gymnasium here on Tuesday in rural 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?