Mayor Bloomberg managed to squeak out something of a victory with yesterday’s agreement on congestion pricing, but because the deal did not give the city the go-ahead to start charging drivers, he faces a political minefield ahead.

While the four-way deal allows the city to start installing cameras to snap images of license plates, it will not be able to charge drivers a penny to be in busy parts of Manhattan until the state Legislature and the City Council vote on the matter.

Getting those approvals is not going to be an easy lift for Mr. Bloomberg, who in the past week has come under fire from some state elected officials who said he didn’t factor in their concerns or answer their questions when he was selling his plan in Albany.

“He’s going to have to revamp his strategy,” Assemblyman Rory Lancman, a Democrat of Queens, said. “He’s got to stop with the public theater and start meeting with individual legislators.”

But securing the city the authority to install the cameras and infrastructure needed to begin charging drivers was a win for the Bloomberg administration because it could give the congestion pricing plan a sense of inevitability. The mayor called the agreement a “critical milestone.”

“We will begin immediately to prepare for the installation of needed equipment to make our traffic plan a reality,” he said.

Aides to the mayor said that assuming the city gets the $536 million in federal money it has applied for, it will also start short-term transit upgrades, which all parties agree must be done before the charge goes into effect. Lawmakers, however, say congestion pricing is far from a fait accompli, and note that the new 17-member commission studying the issue is not bound to anything. The speaker of the state Assembly, Sheldon Silver, said yesterday the process has “just begun.” Until now, Mr. Bloomberg had been adamantly opposed to the idea of a commission, saying it did not go far enough.

In addition to winning over many wary state lawmakers, the mayor will now have to woo City Council members, some who also represent areas outside of Manhattan, where the idea of charging drivers to get into Midtown is being viewed as elitist. Although the council will not be voting to approve the plan, it will be required to pass a so-called home rule resolution asking the state Legislature to take it up.

Speaker Christine Quinn has come out in favor of the plan, which will undoubtedly be an important asset to Mr. Bloomberg, but on a divisive proposal there are no guarantees. Council Member David Yassky said that while there is genuine support and opposition for congestion pricing in the council, mixing in a mayor and a speaker who are in favor of it only boosts its chances.

With a recent poll showing that 61% of New Yorkers are opposed to charging cars to drive into and out of parts of Manhattan, the politicking that is going to be required to close the deal on congestion pricing could consume a large amount of his time for the remainder of his final term. In the past, Mr. Bloomberg has made something of a sport out of taking on unpopular issues — the smoking ban and the property tax hike to name two — and still holding onto his popularity.

Mr. Yassky, a Democrat of Brooklyn, said: “This will occupy a big chunk of effort, but not at the expense of other things. If it was over with and defeated, it wouldn’t take time, but it also wouldn’t be a good thing.”

“Having this move ahead helps his agenda,” he added. “He’s been pitching sustainability as a package and I think it would have taken the wind out of the sails to have the centerpiece defeated.”

Mr. Lancman said the mayor should be wary of letting the idea become his “Moby Dick” — an obsession that diverts him from doing other things.

A push for the congestion charge — which would be the first such charge in the nation and could serve as a model for other cities — comes against the backdrop of a possible presidential run for Mr. Bloomberg. The dean of public affairs at Baruch College, David Birdsell, said regardless of whether Mr. Bloomberg chooses to partner with legislators more or continue his speak-directly-to-the-public campaign, he has a strong case for an independent political movement. “Either approach works into the strategy of promoting a national third party alternative,” Mr. Birdsell said.