To replace Seattle's Alaskan Way Viaduct with another elevated roadway will cost $3.1 billion. With a tunnel, it costs $4.1 billion. These are the high ends of the official estimates, which means we cannot believe them. The true figures will be higher still. They always are.

The tunnel pencils in at an extra billion, which means it will cost at least that much. A billion is $1,750 per man, woman and child in Seattle. Round it up to $2,000.

Taxpayers might ask if the tunnel is worth that much more to them than a new viaduct. Of course, our political leaders don't put the question that way. Instead, we're asked to pay state and local taxes for the cost of a new elevated highway, and the federal government is expected to throw in the extra billion to make it a tunnel.

Right after the Greg Nickels administration said it was expecting this billion, our senior senator, Patty Murray, said she hadn't been consulted about that, and there was no billion available.

In The Sunday Seattle Times, reporter Alicia Mundy wrote that the billion for the tunnel is apparently not forthcoming from Washington, D.C. The federal budget has been blown up by the war, and the Republicans in charge lack the enthusiasm to award a billion dollars to a city that voted 81 percent for John Kerry. Besides, Seattle has not lobbied very hard. The private sector has hardly been heard from.

Part of the private sector doesn't want a tunnel. The North Seattle Industrial Association prefers a corridor open to tank trucks carrying diesel. Other business folk are skeptical of public projects.

In Sunday's story, a lobbyist advised Seattle to make the following argument: If an earthquake knocks the viaduct down, container trains to the Midwest would be blocked and truck traffic delayed. Therefore, people in Chicago should care about keeping the viaduct open here.

The power of that argument — which isn't much — is about the value of a road. But federal money is not about having a road or not. It is about the difference between a viaduct and a tunnel, which is not an investment in transportation. It is an investment in local urban design and real-estate development.

"That makes it harder to sell," says state Rep. Helen Sommers, D-Seattle, longtime chairwoman of the House Appropriations Committee. Sommers says a case can be made for federal money to replace the sea wall, "but that's a long way from a tunnel."

Sommers has the ill manners to apply arithmetic to dreams. Well, somebody in this town has to do it. Seattle thinks it can have the finest of everything: light rail and monorail, streetcars and commuter trains, a bus tunnel and now this waterfront tunnel.

On the City Council, the tunnel skeptic is Nick Licata. "I'm the only one," he says. "It's as if I'm for Ugly Seattle."

Seattle is educated and rich. It wants to decide on aesthetic grounds. It doesn't want to think about the problems of a tunnel below sea level, in which one wall is also a bulkhead against salt water. Let those engineering people figure it out. We're interested in urban design. The waterfront is our front porch. Do it right, we say. Don't be cheap.

I hear it again and again: Don't be cheap. And I think: Cheap ain't the problem.

The problem is money. What do we do if the money doesn't come? At the Washington Department of Transportation, the answer has been that if there is only money for a viaduct, we build a viaduct. "We may prefer to go to Nordstrom but end up at Kmart," said DOT boss Doug MacDonald.

Several councilmen say they will fight to the political death against any new elevated freeway, and we may believe them. It may be, as Port Commissioner Paige Miller says, that a viaduct will be so hated that it is litigated to oblivion. It may be also that the winds in Washington, D.C., shift, and beneficence happens.

Maybe. More likely, our leaders will keep fighting valiantly and electably for a vaporware tunnel, and we continue to talk and talk and talk, and to drive our vehicles on the narrow, bumpy, magnificent and efficient 1953 structure until Mommy Nature orders it closed.

Bruce Ramsey's column appears regularly on editorial pages of The Times. His e-mail address is bramsey@seattletimes.com