When McGinn ran in the primary, his issue was not building the tunnel. "Luckily" for him, that also happened to be the grievance du jour of the Stranger and many Seattle hotheads. In explaining how this worked for the benefit of people reading this out of town, I'm going to use rounded numbers. If you want exact numbers, look 'em up.
McGinn complained that the tunnel would cost $4 billion and was the greatest tax increase in Seattle history. He would stop the tunnel, save the people $4 billion, and build surface improvements instead of replacing the Viaduct. (The tunnel is the proposed replacement for the doomed Viaduct.) He said we should be spending the $4 billion for other purposes, like schools and better bus service.
This wasn't a hard claim to rebut. The tunnel costs were $1 billion from the City, for surface transportation improvements, $1 billion from the County and Port for much the same, and $2 billion from the state gas tax funds, which can only be used for roads, for the actual building of the tunnel. Of the money that would be 'saved' by not building the tunnel, only $1 billion of that was actually from the City, and McGinn was already proposing the spend the money 'saved' by cancelling local street improvements on the exact same set of improvements if he was elected.
None of the McGinn supporters ever understood this (or if they did, they pretended not to understand it). Others did, and the long pregnant silence when McGinn looked for endorsements was a solemn tribute to the profound discomfort felt by many at the sight of such demagoguery.
Next up: Bicycle riding McGinn! Streetcar riding McGinn!