The Mackinac Bridge is seen in this February 2023 photo. Michigan Attorney General Dana Nessel’s case looking to shut down a four-mile section of Enbridge’s Line 5 oil and gas pipeline resumed Monday. (Laina G. Stebbins/Michigan Advance)

LANSING — Arguments in Michigan Attorney General Dana Nessel’s case seeking to shut down a 4-mile section of Enbridge’s Line 5 oil and gas pipeline resumed Monday in the state’s 30th Circuit Court, as her office squared off with the Canadian energy company.

Assistant Attorney General Daniel Bock challenged the validity of the 70-year-old easement allowing the pipeline to operate on the lakebed in the Straits of Mackinac where Lake Michigan and Lake Huron meet.

Meanwhile Enbridge attorney Phillip DeRosier argued federal regulators exercise sole authority over pipeline safety, saying challenging the pipeline’s operations in the Straits would violate a 1977 treaty with Canada.

Monday’s hearing came after years of legal maneuvering kept debate outside of the courtroom.