What does Shelly want?

That's the question being asked again and again in Albany and City Hall. As the battle over the Jets West Side stadium enters a make-or-break week, Assembly Speaker Sheldon Silver holds the cards. So far, he has said no. Or is it maybe? Or maybe it's yes?

Take your pick, for Silver is the Sphinx of Albany. He's so good at hiding his bottom line that rivals go nuts trying to figure out what he wants. Sen. Majority Leader Joe Bruno, often frustrated by Silver's negotiating style, once mimicked a bargaining session this way:

Bruno: I see you're selling a house. How much do you want for it?

Silver: What do you got?

Bruno: How about $100?

Silver: Not enough.

Bruno: Well, how much do you want?

Silver: What do you got?

Bruno: How about $110?

Silver: Not enough.

Bruno: Well, how much do you want?

Silver: What do you got?

Bruno: $120.

Silver: Not enough.

"It's crazy," Bruno laughed. "You end up bidding against yourself because you never know what he wants."

Silver's stadium role has become even more important because Bruno recently told a group of city labor and business leaders he was ready to vote yes. "He told me, 'I'm for it on the merits, we just have to work out the politics,'" said one supporter.

A Bruno spokesman, John McCardle, confirmed the comment, but said new questions have since come up.

"Some documents we got show the public commitment is probably double over what we thought," McCardle said. This week looms large. A ruling is likely on some of the lawsuits filed against the stadium. And Gov. Pataki and Mayor Bloomberg, if they get a favorable ruling, want to force a Friday vote at the Public Authorities Control Board. For the stadium to pass, Silver and Bruno, along with Pataki, must say yes.

If all that happens, Olympic backers hope for a good report from the International Olympic Committee on June 6. The bids of the five finalists for the 2012 Games — New York, Paris, London, Madrid and Moscow — will be assessed. Bloomberg's dream is that winning the first round in court and getting Silver and Bruno to support the stadium will give the city a big boost in the evaluation.

Both backers and opponents are planning TV and radio ads, at a total cost of perhaps $500,000.

Almost all of it will be aimed at Silver. He has already reaped benefits for his lower Manhattan district, including a new school, as Bloomberg tries to win his vote. Pataki has opened state coffers, too, and is trying to jump-start work at Ground Zero. Suddenly, he and the mayor are finding hundreds of millions of dollars for downtown development.

As I've written, this would be bribery if they were trying to influence Silver with private money. But it's public money, so it's called negotiation.

Will Silver go for it? He has said the West Side plan, with its 24 million square feet of office space, hurts attempts to lure jobs downtown. He wants a Marshall Plan, but has not said whether even that would win his okay. Indeed, he has promised only that the city would get "a stadium" — not necessarily in Manhattan — if it wins the Olympics.

One Jets lobbyist thinks Silver will come around. "There's no upside for Shelly to vote no," he said. "He now has the most significant leverage he's had in 10 years as speaker. It's closing time and I think he'll make a deal."

But who knows what Shelly wants.