A friend who is a critic of Ren Square asked me on Saturday: "Is there any way to stop that thing?"

My response: Nope. If the county wants it, we'll get it. The city's not likely to stand in the way.

What a difference a couple of days make.

On Monday, Mayor Bob Duffy said he wants to dump most of Ren Square. He wants the MCC facility. But he wants the theater removed from the plan and its land made available for private development.

And he wants the bus station - Ren Square's very foundation and its raison d'être - scaled back to some kind of bus turn-around and a shelter for passengers.

Duffy is, as he noted, only one vote out of four on the Ren Square board. He can be outvoted. And no doubt he will be.

But that doesn't guarantee that the project will move ahead. The real power right now lies in City Council, which has to approve several Ren Square requests: changing the use of Mortimer Street, abandoning Division Street, selling a city-owned lot to Ren Square, and using eminent domain to acquire private property on the site.

Duffy will use his considerable powers of persuasion to try to keep City Council from going along unless he gets the changes he wants. Council members - all of whom are Democrats, and some of whom have been fairly strong supporters of Ren Square - will have to decide whether they'll side with their Democratic mayor or with the Republican county executive.

You can't blame Maggie Brooks and others on the Ren Square board for being upset. Until late April, Duffy had given no indication that he would try to block the plan. His representative, in fact, voted with the rest of the Ren Square board recently to let the project move into the final design stage.

The division over the project isn't along party lines, by the way. A fair number of Democratic officials support Ren Square, not only for the construction jobs it will create but also because they believe that even without the theater, it will be a dramatic improvement over what's on that block now. They, like the majority of the Ren Square board, want the theater parcel cleared and cleaned up, even if the theater never materializes.

And, they warn, without the bus station, there'll be no federal transit funds. Without that money, there'll be no new MCC campus.

But Duffy is making a compelling case - late, perhaps, but compelling. Rational. And important.

What is best for the city? Is a bus station on prime downtown real estate the best we can do? Taxpayers will spend millions of dollars to build it. We'll spend millions more to operate it - every year. Do we build the bus station simply so we can use federal transit money for the MCC campus? Can't we get the buses off Main Street and provide shelter for riders in a better - far less expensive - way?

Yes, the bus station will create a lot of construction jobs. But they'll end when the project is built. The operating costs will be with us forever.

If we were starting all over, knowing what we know now, I can't imagine that Ren Square would get off the ground. We are where we are, though. The question - for City Council, and for all of us - is just what the mayor says: What's best for the city?

Ren Square's supporters have billed it as an economic development and downtown revitalization project. In an earlier incarnation, with a design by Moshe Safdie, it might have been both. But it is neither, now.

Ren Square was flawed from the start. It was a bus station trying to justify its cost: the sugar coating used to sell the public on a plan to give bus riders a warm place to wait. (Or a plan to create jobs. Or, if you want to be cynical, a plan to win the loyalty of the construction trade unions and donations from engineering and construction firms.)

All these years and around $20 million later, with Safdie gone, two of the three theaters jettisoned, the third theater very much in doubt, we're working on the final design for what's left of Ren Square: a bus station and an MCC facility.

The members of City Council have a tough decision to make. And they may be in the uncomfortable position of thwarting a plan for a nice, warm waiting area for bus riders, many of whom are low-income city residents.

This could get ugly. It could get litigious, if the city and county can't come to a reasonable compromise. The arguments and the delays themselves could jeopardize the federal funds. They could bring back the hostile climate that existed between Jack Doyle and Bill Johnson, hostility that the public clearly didn't like.

But in publicizing his concerns, Bob Duffy has absolutely done the right thing. He has suggested that we can build a less expensive bus facility. He has spoken the truth about the theater's lack of funding and the effect that has on the future of that site.

I can see logic in the arguments of both sides. I'll keep weighing those arguments, and so should you.

I have no idea how this will play out. I do have a hunch that Senator Chuck Schumer, who has been a crucial supporter of the project, will sidle over to the mayor's viewpoint.

Another hunch: City Council will go along with the mayor. The Ren Square board won't.

A final hunch: The enthusiasm for Ren Square is a thing of the past. In terms of public opinion, the mayor wins.