Just two months into the job, Sally Clark has already positioned herself to cast one of the most important, and potentially contentious, tiebreaking votes of the year.

The vote itself won't happen until later this year. The debate, however, has been raging since at least early 2004, when the so-called "no-build" proposal for replacing the Alaskan Way Viaduct (a proposal proponents like Peter Steinbrueck now prefer to call the "surface/transit" option) first began to circulate. Mayor Greg Nickels, who wants to replace the viaduct with a $4-billion-plus cut-and-cover tunnel, wants to put just two options on a November advisory ballot: the tunnel, plus an aerial viaduct rebuild option Nickels has dubbed "the Big Ugly."

Clark will be Steinbrueck's fifth vote for putting the third option on the ballot, joining Nick Licata, Richard Conlin, and Tom Rasmussen.

Surface-option proponents say eliminating the third alternative creates a false choice, giving voters the impression that their only options are an ugly aerial rebuild and an unaffordable tunnel. Their arguments are gaining acceptance among many, like Clark, who don't necessarily support the surface option but who believe voters should be able to choose among all the alternatives, not just two. "I get a ton of e-mail from people who think we should have all the options," Clark says. "I would like to have enough information for people to legitimately consider" the surface option, she adds.

Mayor Nickels and other tunnel proponents oppose putting the surface option on the ballot, arguing that the choice between three options will "confuse" voters and send an unclear message. Although Nickels's communications director, Marianne Bichsel, did not return calls for comment, both Nickels and the Washington State Department of Transportation (WSDOT) have argued that any option that reduces capacity in the Alaskan Way corridor (which currently carries 110,000 vehicles a day) would not be eligible for state funding. State legislation providing $2 billion in viaduct funding does say that the state will not provide funding for any project that "could have the effect of reducing roadway capacity" on the viaduct replacement; however, as People's Waterfront Coalition founder Cary Moon points out, the legislation could be revised to allow the surface option if the voters chose it in November. Steinbrueck, the most vocal supporter of the surface option, says WSDOT is "a road agency, not a transit agency. They don't want to see anything but full and complete auto-capacity replacement."

The argument sounds compelling: After all, if the state fails to replace the viaduct's capacity, won't the traffic clog city streets, resulting in total, calamitous gridlock? That's certainly WSDOT's argument; they claim that without the viaduct, the city's "mobility, economic vitality, and quality of life" will be harmed. But others, such as Steinbrueck, argue that WSDOT's goal should be moving people, not cars; they note that as soon as road capacity is increased, it tends to fill up—a theory known as "latent demand." Conversely, when driving becomes harder (because, for example, a road shuts down) people find new routes, eliminate or combine trips, or find alternative ways to get around. Steinbrueck also notes that Nickels's pro-freeway position is "diametrically opposed to his stated goals under the Kyoto Protocol," which calls for the city to meet the Kyoto requirements for greenhouse-gas emissions by 2012.

Not only does the mayor's tunnel plan contradict his position on global warming, it isn't funded, and much of the money Nickels says he has is far from secure. The largest single chunk of funding for the tunnel, $200 million, would come from the Port of Seattle, but so far, no one on the port commission has said whether they'll vote to provide the money. Three out of four voting port commissioners (Commissioner Alec Fisken will recuse himself from viaduct-related business because he works for the city) will have to support paying for the viaduct before the $200 million is released. John Creighton, a port commissioner elected last year, says "no funding has ever been committed" to the viaduct, adding, "I just think $200 million is a lot of money to give away with no strings attached." While Creighton says he personally favors the tunnel, "I need to be convinced either the port or the region is getting substantial value in return for any port participation."

barnett@thestranger.com