What will Boston do with Northern Avenue Bridge?

The Northern Avenue Bridge lit up at night.Jessica Rinaldi/Globe Staff/File/Globe Staff

What did Joe Moakley want? What would Tom Menino have done? In 20 years, will we be asking ourselves: How did Marty Walsh feel about the century-old Northern Avenue Bridge?

I’m loath to make another bet with the mayor, but I wouldn’t be surprised if we’re still talking about the rusty metal bridge in 2034, because the more things change around here, the more they . . . well, you know. It just might be easier to host the Olympics than agree on what to do with that bridge.

The structure’s abrupt closure last week — it was deemed unsafe even for pedestrians — is already fanning the flames of a debate that stretches back to the 1980s. Moakley, the late South Boston congressman who championed the Seaport District back when the area was a bunch of empty parking lots, wanted the bridge demolished. Menino, the recently departed mayor, tried to sell the city-owned bridge, then wanted it torn down, only to come around to the idea of preserving it.

In between, there have been a half-dozen proposals to redevelop the bridge, including one from Bob Beal to create the Ponte Vecchio of Boston, our version of that fabulous span of shops over the river in Florence. But mention such grandiose plans and invariably you start to hear grumbling from the practical minded. Let’s keep it simple and the costs low. Just bring the damn thing down and build anew so both pedestrians and cars can use it again.

Now before we get too far ahead of ourselves, that sound you just heard was the unmistakable sloshing of preservationists paddling up Fort Point Channel coming to the rescue of a bridge that has long served as a historical gateway between the Financial District and the South Boston Waterfront. We may never get the tens of millions of dollars needed to restore the bridge, but at least we had fun dreaming about it.

If you can believe it, there are even more people with a vested interest. No doubt, the judges and lawyers who work at the Moakley federal courthouse will want to weigh in again; they consider a functioning Northern Avenue bridge to be a vital option for getting in and out of the increasingly congested Seaport District. Reactivating the bridge has also been part of a waterfront transportation plan currently being drawn up.

If Walsh wants to build a new bridge, he needs a permit from the Coast Guard, because it would span a federal waterway. Yes, that part of the channel remains active — some small boats and water taxis still use it — but the Coast Guard is one group that doesn’t seem to have a strong opinion about what happens.

“We don’t have any agenda concerning the bridge,” said John McDonald, bridge manager and specialist at the First Coast Guard District in Boston.

What has really stood in the way of getting anything done is money. In 2007, John Hynes, who is developing a large swath of the Seaport District, offered to contribute $5 million toward fixing the Northern Avenue structure; the city said “No thank you,” knowing that it would take a lot more to rebuild it. The current estimates range from $8 million to just take down the bridge to $60 million to fully rehab it.

Hynes instead went on to build the innovation center District Hall as part of his development deal with the city. He said he would have liked a new bridge.

“It’s so frustrating,” he said.

But in the perverse world that is ours only, the emergency closing actually might force us to focus.

“I’m thrilled. People are going to pay attention to it,” Hynes said. “Now we can get out of the fantasy world of urban design and get into the practical world of urban transportation.”

What will also focus the mayor is the embarrassment of a shuttered old bridge in a part of a town that is supposed to represent our shiny new future.

So Mayor Walsh, here’s New Year’s resolution number one: Set yourself a deadline. Spend 2015 getting everyone around the table to figure out what do about this bridge. This time next year, have a plan we can all agree on.

I can tell you already there’s consensus that the bridge should be accessible to some combination of pedestrians, bikers, and perhaps cars, too. The big question that remains is: At what cost? Do we go for the full restoration, or is there a cheaper alternative?

One thing’s for sure: Count on money being hard to come by. That means you’ll need to push for creative solutions from the private sector. Use to your advantage all the developers and deep-pocketed companies moving into the Seaport District that want — and will probably pay for — better transportation options.

We need to do something about our bridge to nowhere. Don’t let history repeat itself here.

ONLINE UPDATE: I heard from US Representative Stephen Lynch, who represents South Boston, late Tuesday night. Lynch said he supported “updating the bridge for vehicular and pedestrian traffic,” while artfully dodging the issue of restoration or new construction. “Over the years, I have worked to secure over $9 million in federal funding for improvements to the Northern Avenue Bridge,” he said. “We need a functional Northern Avenue Bridge to accommodate the growth in the area.”