Not a lot of new ground broken in tonight's final major televised debate between Mike McGinn and Joe Mallahan. The debate aired at 9 p.m. on KOMO and was moderated by newscasters Kathi Goertzen and Dan Lewis.

As usual, the sharpest moments came again when Mallahan and McGinn were asked which one could be best trusted to protect Seattle's interests when it comes to the planned $4.2 billion waterfront tunnel project.

Mallahan returned again and again to his management experience as a T-Mobile vice president, saying he'd work to bring in the project on time and on budget.

"Mike has zero management experience. He has never managed a budget of even $1 million," Mallahan said.

McGinn hit back with one of his better lines: "We elect leaders. We hire managers."

What is important is not a business background, McGinn said, but a strong understanding of the risks to the city if there are billions in overruns, ffor which the state Legislature has said Seattle would be responsible.

He envisioned a worst-case scenario in which a deep-bore tunneling machine gets stuck underground -- just like two such machines are in King County's Brightwater project.

"My position is we shouldn't proceed until we have an understanding of who is going to pay for cost overruns," McGinn said.

Mallahan said he'd work to get that cost-overrun provision reversed by the Legislature, but said the project should go ahead as planned.

"This is a decision that took us eight years to get to and we're all frustrated it took so long...
But it's time to get moving." Mallahan said.

He said McGinn's cost arguments about the tunnel are a smokescreen anyway -- McGinn's real goal is to prevent any new highways from being built.

"I just can't trust that he will manage this project with any vigor or earnestness," Mallahan said. "What he wants to do is tear the viaduct down replace it with nothing and flood our streets with 70,000 more vehicles."

Responding to McGinn's frequent citation of an Oxford University study which found mega-projects almost always go over budget, Mallahan attempted a joke:

"There is a University of Washington study that says 90 percent of politicians that quote Oxford University studies just don't want to get anything accomplished."

You can view the entire debate here.