The Bank of New York has come to Governor Pataki’s aid in the legal battle against Mayor Bloomberg’s scheme to refinance New York City’s debt. The bank may say that it is only upholding its fiduciary duty as a trustee on behalf of bondholders who have already lent money to the state, but its entry into the dispute will shore up the position of taxpayers across the state.

As cooked up by the Legislature last year, the refinancing deal allows the city to shirk its remaining debt from the fiscal crisis of the 1970s, shifts the burden to the state, and stretches the repayment schedule to 2034 rather than 2008. These maneuvers would save the city $2.5 billion over the next five years, but cost the state $5.1 billion over the next 30. We fail to see why future New Yorkers should pay such a high price for the errors of their ancestors.

Mayor Bloomberg welcomed this latest piece of fiscal fecklessness from Albany and is eager to consummate the deal before the end of his fiscal year in June. But Mr. Pataki vetoed the legislation and, when he was overridden, sued to block the Bloomberg bonds from going on the market. The state’s highest court, the Court of Appeals, will hear the case later this month.

Mr. Pataki’s stand has been a lonely one. Of all the politicians who claim to represent the interests of the taxpayers, the only one in the governor’s corner is the comptroller, Alan Hevesi, which is no small thing in partisan terms, Mr. Hevesi being a Democrat. As reported by our Wm. Hammond Monday, however, the governor is getting a measure of support from the private sector, in the form of a friend-of-the-court brief from the Bank of New York.

The bank got involved because it rep resents investors who lent several billion dollars to an obscure vehicle for state borrowing known as the Local Government Assistance Corporation. The refinancing plan essentially calls for this corporation to pay off the Bloomberg bonds at the rate of $170 million a year, drawing from the same portion of sales tax revenue that it uses to cover its own debts.

The bank — echoing an argument from Mr. Pataki’s lawyers — contends that this new obligation might prevent the corporation from making good on its commitments to existing bondholders. This possibility, even if theoretical, would be a disservice to the legions of good people who have afforded credit to the state and city of New York.

This is but one of several arguments against the plan. The deal also improperly commits the state to make future payments without annual approval by the Legislature and allows the city to borrow money without pledging its “full faith and credit” — both being violations of the state constitution.

Weighing in with anti-taxpayer briefs on the other side are the speaker of the assembly, Sheldon Silver, and the New York State Conference of Mayors. They join the city’s lawyers in claiming that this deal is not fundamentally different from dozens of other ill-conceived borrowing schemes that have survived legal challenge in the past. Or, in other words: It might be wrong, but everyone does it. If some clauses of the legislation explicitly violate the constitution, they say, the judges should construe the offending words as “inartful drafting” by a sleep-deprived Legislature and strike them out with their judicial erasers.

This latter argument, as embarrassing as it is to state lawmakers, was explicitly endorsed by Mr. Silver. We hope the court will instruct the Legislature to fix its own mistakes. No doubt the reason Mr. Silver is in court fighting against the taxpayers at this juncture is that he recognizes that, since their eyes have been opened by Mr. Pataki’s leadership, the Legislature is unlikely to muster majorities — let alone veto-proof majorities — to ratify this scheme a second time.