Now they're saying the F-word in this arena debate.

Fair.

It's a polarizing notion. Fair to one person is a fleecing to another. We're used to negotiations resulting in a winner and a loser. Fair is probably best defined as an event where cotton candy is consumed.

But that's where we are with investor Chris Hansen's effort to build an NBA/NHL arena in Sodo — fair. What's fair? To his credit, Hansen has sought fair from the beginning, and he has pledged $290 million of private money to prove it. That's why he has made it this far, because his group's willingness to pay for nearly 60 percent of a $490 million arena is a stunning commitment in modern-day pro sports business. He often calls his proposal fair, and he has a large, vocal contingent that agrees.

Still, to a city with diverse interests, needs and problems, fair is about as complicated as explaining why the Mariners can't hit. As Hansen's dream shifts from the argument phase to a possible deal consummation, victory boils down to this tricky question: Uh, is there such a thing as unprecedented fairness?

The Seattle City Council hopes so. Actually, eight of its nine members (Bruce Harrell was the lone exception) demanded as much in a counterproposal sent to Hansen on Monday. Even though Hansen's arena plan minimizes financial risk with eye-opening detail and ingenuity, the city council thinks he can do more. Most notably, it has a crystallized vision of how he can help solve some of the infrastructure problems in Sodo.

The city council overshadowed the Metropolitan King County Council's 6-3 vote to approve Hansen's plan by revealing its request Monday. Hansen is asking for up to $200 million — $120 mil from the city, $80 mil from the county — in bonds for his sports and entertainment arena. His clever plan to pay them back includes using tax revenue that only the building could generate, so that no new taxes are needed. The city council is requesting that some of the arena's tax revenue be used for improvements to traffic and freight mobility in Sodo.

It is also seeking more financial protections and some specific assurances KeyArena won't grow old alone over there in Lower Queen Anne, but diverting some of the new arena's revenue is the biggie.

If you're for the arena and have been impressed by the measures Hansen took upfront to make this a good deal for both parties, then it's impossible to resist outrage that the city council is asking Hansen to fix too many of the city's problems. Why risk ruining a great opportunity in pursuit of perfection? It's a valid concern, and the city council had better be careful with this negotiation.

There's no question it's unfair to demand Hansen be the city's elixir. But perhaps there is some middle ground in which he could be a catalyst to help the city take proactive measures to solving the Sodo transportation problem.

While trying to explain their thinking, city council members Sally Clark, Mike O'Brien and Tim Burgess revealed the council is working toward a positive conclusion.

"We're saying today that we want to get to yes," Burgess said.

Said O'Brien: "We're looking for some creative ideas."

So, what's fair? It would be negligent and unfair for the city council to ram a deal through without concern and some level of mitigation for traffic and freight mobility in Sodo. It also would be foolish and unfair to toss away such a sweet deal from Hansen simply because of an issue that he didn't create. And if a deal can't be reached with Hansen, the traffic problem still remains.

Hansen is willing to do his part. But his group won't be a magic ATM.

"There's a matter of fairness," Hansen said last week when I asked him about concessions to improve infrastructure. "We're willing to listen and do our fair share. As long as it's not unfair and so substantive that it makes the deal unworkable, we're open."

Asked about wiggle room in his proposal, Hansen said, "That breaking point is pretty close to where we're at."

Over the next week or so, the city council will figure out that breaking point. It shouldn't cross it, though. There's nothing wrong with trying to make a sweet deal even sweeter. But watch out for cavities.

During the county council's meeting, Julia Patterson explained her yes vote, lauded this plan as much better than the Safeco Field and CenturyLink Field stadiums that she opposed earlier in her political career and emphasized, "Nothing is completely risk-free. There is no such thing."

It was the right sentiment. Then again, County Councilmember Peter von Reichbauer, a stadium proponent in the past, voted no and relayed something he once told Hansen, "At the end of the day, there are going to be three issues: transportation, transportation, transportation."

He's right, even if you disagree with his vote. And for Hansen to earn the city council's approval, he has to spearhead attempts to improve traffic in Sodo. The city council alluded to discussions in infancy with the Mariners, Seahawks, Sounders FC and other Sodo businesses about how they could help the area. And the letter to Hansen mentions that a share of the arena's tax revenue could assist the city in leveraging state and federal government funding to lessen the Sodo congestion.

Hansen has a clever proposal. The city council has been equally clever in countering. Now, it's about fairness and honest negotiation. If that happens, a deal gets done, and everybody gets something out of it.

If not, well, it wouldn't be fair to speculate how ugly that could be.

Jerry Brewer: 206-464-2277 or jbrewer@seattletimes.com. On Twitter @JerryBrewer.