When it comes to the controversial Line 5 petroleum pipeline that sits under the Straits of Mackinac, Gov. Gretchen Whitmer has consistently called for a strategy that will "get the pipeline out of the water," as soon as possible. 

Environmental groups want the 4.5-mile-long section of the Enbridge pipeline between St. Ignace and Mackinaw City completely removed from the lakebed. Others, including the Michigan Building and Construction Trades Council, support a plan approved by state lawmakers and Gov. Rick Snyder late last year that essentially grants approval for a plan to encase the pipeline and other utilities in a tunnel bored in the bedrock well below the Straits. 

What Whitmer means by getting the pipeline out of the water isn't altogether clear, but for her the tunnel option seems to be very much in play. “If it can help me get the pipeline out of the water earlier, that’s something that is worth talking about,” Whitmer said in an April 15 interview with the Detroit News editorial board.

Construction of the pipeline 100 feet through bedrock below the Straits would be a multiyear effort that's expected to cost up to $500 million and create hundreds of building trades jobs in a region that rarely sees projects of such a magnitude. The dual 20-inch steel pipelines currently under the Straits are a relatively small part of the entire 645-mile Line 5 pipeline from Superior, Wisconsin to Sarnia, Ontario. But the increased clamor over the potential for a petroleum leak and the damage such an event would do to the Great Lakes has in recent years increased the clamor for replacing the pipes, which have been in place since the 1950s.

Enbridge spokesman Ryan Duffy issued a response to Whitmer's comments: “We continue to provide information to the governor’s office and to seek clarification from the administration on a path forward for the tunnel project. We believe the project is the best way to protect the waters of the Great Lakes while ensuring families, manufacturers and other businesses safely receive the energy transported through Line 5.”

With the legislative action late last year in place to create a Line 5 Mackinac Straits Corridor Authority to oversee construction of a utility tunnel, there is hardly a consensus that Whitmer ultimately has the authority to change or halt the course of the project, if that's what she wants. 

New state Attorney General Dana Nessel has issued an opinion that state lawmakers violated the Michigan Constitution when they created the tunnel authority, and Whitmer subsequently ordered state agencies to halt any planning for the tunnel. 

But for what's next, the ball is very much in Whitmer's court. The state tunnel authority is essentially dead in the water with the positions taken by Whitmer and Nessel. But does Whitmer really want to take on a potentially lengthy and costly legal battle that would ensue - while the pipelines remain in the water? 

What happens if Whitmer/Nessel sue and a court overturns last year's legislative action approving the tunnel authority? Then it's back to square one, without the tunnel option, and the pipelines are still in the water.

And would a court find that the federal government, not the Michigan Legislature, has the ultimate authority over a pipeline that crosses state lines? 

Nessel entered the fray this April 29, saying that she would move to shut down Line 5 if the governor doesn’t find a “swift and straightforward” resolution to the issue.

As this political and potential legal matter plays itself out, Enbridge to an extent has the luxury of time on its side. It continues to pump petroleum products through the pipelines at the Mackinac Straits - with no executive, legislative or legal order in place telling it to shut down Line 5 - and it is continuing to execute its plan to build the tunnel.

Enbridge's Peter Holran told a building trades audience in March that the obstacles will be overcome. "We're very cognizant of what is in front of us," Holran said. "We're very thoughtful about how we will be moving forward. But let me say, we are going to build the tunnel. We are going to build the tunnel."