As Enbridge Energy prepares to finish rebuilding an oil pipeline across rural northern Minnesota, protesters are occupying part of the construction area and pledging a "summer of resistance" on the ground and in court.

Enbridge, which has obtained all necessary state and federal permits for the Line 3 project, says it will be finished by year's end.

The Canadian company describes it as essential for reliable oil supplies in both nations, saying the plan has undergone rigorous environmental permitting and will boost Minnesota's economy. Opponents contend it endangers waterways, violates indigen...