Enbridge Inc. has won the second round of its legal battle against fossil fuel foes to keep its 540,000 b/d oil Line 5 across the Straits of Mackinac between Lake Huron and Lake Michigan.

The Michigan Court of Appeals upheld a trial judge’s decision in favor of a 2018 agreement with the former Republican state administration to let the pipeline stay by burying it in a new $500 million utility tunnel.

The verdict rejected a claim by the current Democrat administration that the deal violates the state constitution because the title of the bill that the legislature’s Republican majority passed to ratify it failed to describe the project completely.

The three-judge appeal panel’s unanimous verdict noted that the bill title mentioned the utility tunnel. The decision added, “The title of an act is not required to serve as an index to all of the provisions of the act.”

A further appeal by the pipeline’s opponents is expected to the Michigan Supreme Court. State Governor Gretchen Whitmer and Attorney-General Dana Nessel won office in 2018 on Democrat election platforms that committed to discard the pipeline strait crossing.

An Enbridge statement Thursday said preparations continue for building the safer buried version of Line 5. “Pending receipt of all permits and regulatory approvals, we anticipate completing construction of the tunnel in 2024.”

Earlier this month Enbridge also won a case in the United States Sixth Circuit Court of Appeals. The verdict upheld the firm’s Line 5 oil spill response plan against opposition by the National Wildlife Federation.

But the Canadian oil and gas pipeline conglomerate is still contending with three other lawsuits — two in Michigan and one in Wisconsin — that aim to scrap the 67-year-old Straits of Mackinac crossing.

In Michigan a verdict is awaited on a lawsuit filed by Nessel, seeking to cancel an easement the state granted in 1953 to enable construction of Line 5. In a second pending Michigan case, northern native tribes and landowners are challenging the safety of Line 5 hardware. In Wisconsin, Enbridge faces a lawsuit against Line 5 by the Red River Band of the Lake Superior Chippewa.

All the lawsuits recite legal variations on protest themes that the oil pipeline poses threats to the Great Lakes environment, communities, and native tribes.