Attorneys sparred before a federal judge in Minneapolis on Monday over whether the Metropolitan Council has gone so far on the Southwest light-rail project that it has predetermined the outcome and should be ordered to restart the local approval process.

The request to U.S. District Judge John Tunheim is the heart of a lawsuit that is the last local threat to building the commuter rail line linking Eden Prairie and downtown Minneapolis, which the council wants to start operating by 2019.

Tunheim said he will rule in the lawsuit brought by Lakes and Parks Alliance of Minneapolis "as soon as possible." He ruled last Friday on motions that narrowed the scope of the group's case.

The alliance filed a lawsuit to block the current route, saying it threatens to destroy the Kenilworth trail and harm the surrounding lakes and parks.

Lewis Remele Jr., arguing for the alliance, said the Metro Council's actions have ruled out other reasonable route options by concentrating its engineering and city approvals on just one route, along the Kenilworth corridor. Under the proposal, the light-rail cars would share the line with freight trains and recreational paths, diving underground at one point and crossing a channel between lakes over a bridge.

"We're getting into a wonderland situation where you have the verdict first and the trial later," Remele said.

He argued that local approval should be required again after supplemental environmental studies released later this year determine the impacts of the Kenilworth route and how to mitigate them.

Charles Nauen, representing the Met Council, argued that there is ample legal precedent for agencies proceeding on a two-track process by doing engineering and other preparatory work while they analyze environmental impacts. The critical matter is whether they enter construction contracts or make other agreements that commit to a specific outcome before environmental studies are complete.

Nauen argued that there's been no predetermined outcome, no limit on an eventual choice of routes and the council has complied with the law requiring municipal review of light-rail proposals. He also said municipal consent isn't required for a project to go ahead.

"How does this not look like a done deal before the process is finished?" Tunheim asked Nauen.

The Met Council's attorney responded that choosing a route "is an iterative process until the line is crossed where there's a binding commitment."

The alliance is asking Tunheim to order a new round of city approvals after the study is done.

Steve Brandt • 612-673-4438

Twitter: @brandtstrib