With each passing day I'm more convinced that there's no longer any need to decry the proposed deep-bore tunnel replacement for Seattle's Alaskan Way Viaduct. Because the tunnel is already on death row. Not because the urban greens are winning (they aren't), but because we won't be able to pay for it.

Funding the deep-bore tunnel has been problematic from the start, as exemplified by the notorious cost overruns provision. And as time passes, the financial outlook has only become more dubious, to the point where it's hard not to suspect that eventually the state will end up pulling the plug.

The state currently has four multi-billion dollar highway megaprojects on its to-do list: the deep-bore tunnel, the 520 floating bridge, the Columbia River Crossing bridge, and the North Spokane Corridor. The 520 bridge is still $2 billion short, and the plan for funding the Columbia River Crossing is still up in the air. From the perspective of the state legislature, there is no question that, as the transportation budget gets squeezed, either of these projects would have higher priority than Seattle's deep-bore tunnel.

Meanwhile, gas-tax revenues are declining; Initiative 1053 will likely make it much harder to implement tolling or increase the gas tax; and the state may be on a collision course with its constitutional bond limit, depending on whom you believe. In any case, the debt service on bonds is likely to become politically radioactive statewide.

And as for the tunnel, the list of setbacks just keeps growing longer: The $300 million contribution committed to by the Port of Seattle has yet to materialize; floating bonds on $400 million of toll revenue may prove problematic, as noted above; the EIS does not include a complete analysis of the effect of tolling; the state had to raid the contingency fund to keep the bidding process alive; the cost overrun provision continues to be challenged; Seattle's Department of Transportation appears to be distancing itself from the project; and the firm selected to build the tunnel has a checkered history.

Would the state go so far as to yank the gas-tax funds that have already been allocated to the deep-bore tunnel? Could the massive bureaucratic wheels be stopped, now that they have slowly begun to grind forward?

We all know that Seattle-bashing is an exceedingly popular pastime for state politicians from outside the city. I don't find it hard to imagine a statewide political groundswell to take away elite Seattle's gold-plated gift from state taxpayers. It won't be long before Gregoire is replaced. And that $2.8 billion would go a long way toward filling the funding gaps for the 520 bridge and/or the Columbia River Crossing.

None of this is to say that if the tunnel dies, we'd necessarily end up with a better solution to replace the viaduct. Nor would it be a good outcome for the tunnel money to be reallocated to other freeway megaprojects, because as I've argued previously, every dollar we spend on increasing car capacity is money down the toilet.

Alas, the I-5/Surface/Transit alternative is not cheap either, though it would be about $1 billion less than the tunnel. And at least it isn't a "gargantuan monument to the past," as Sightline founder Alan Durning has described the tunnel.

Maybe the state would throw a hissy fit, dismantle the viaduct, hand over Highway 99, and wish Seattle the best of luck with it. But maybe that wouldn't be the end of the world. People would adapt. Seattle would figure out how to efficiently utilize the street grid that's already on the ground. The existing waterfront street would suffice. The demand for transit would rise, providing a prod for transit agencies to beef up service. People would drive less. People would live more locally. And there's a word for all that: sustainability.

The deep-bore tunnel is dead! Long live the deep-bore tunnel!

(Want to hear both sides of the deep-bore tunnel debate? Come to City Hall, 600 Fourth Ave., tonight at 7 for PubliCola's tunnel forum, featuring Mayor Mike McGinn, city council member Mike O'Brien, People's Waterfront Coalition founder Cary Moon, state Sen. Ed Murray, city council member Tom Rasmussen, and King County Labor Council executive secretary Dave Freiboth.)