Between the city and the state, government took in $10 billion more of our money than was really needed over the last year. That’s absurd.

The city and state budgets are both up about 6% over the last year, with the city growing from $50 billion to $53 billion and the state from $106 to $113. There could have been another $10 billion in tax cuts and the government would’ve had enough money to function.

For obvious reasons, officials would rather be in the black than in the red – so they low-ball revenue estimates and often wind up with more cash then they really need to run government. To some extent that makes sense, because a surplus is preferable to a deficit.

But in flush times like this, budget makers’ habitual conservatism is unfair to taxpayers.

City officials have predicted budget deficits into the future for years. Sometimes they’re right, like in 2002 and 2003 when Mayor Bloomberg raised property, sales taxes and income taxes and still needed help from Albany. The economy was in a rough patch even without the 2001 terrorist attacks, which only made the budget situation more difficult.

Nearly every year, the city and the state separately predict that the future three years will look bleak. During downtimes those projections are correct. In the last few years they’ve been flat out wrong – and taxpayers pay the price when budget makers cry wolf. Last year was supposed to see a $7 billion deficit, but wound up with a record $3.5 billion surplus.

This year is also shaping up to be about quite rosy. In the fiscal year ending today, New York City enjoyed a $5.5 billion budget surplus. That’s a whopping 10% of next year’s $53 billion budget.

The mayor’s bullpen aides will surely argue with the $5.5 billion figure, arguing that $2 billion for a health care fund doesn’t count as a surplus. But the reality is the health care fund wouldn’t exist without the surplus.

The remaining $3.5 billion of the surplus will be rolled over to cover next year’s projected $4 billion deficit. Sound familiar, projecting a big deficit only to see a surplus after all? Get used to the trend. City officials predicted $4 billion deficits for the next few years, but they’re not likely to materialize unless terrorists strike, Wall Street plummets, or the alleged real estate bubble bursts. Those calamities would make the doomsday budget projections look correct. More likely, those projections are just wrong.

The upside to bleak expectations is they prevent spenders – known professionally as politicians – from going on a binge. But these bleak expectations also keep tax rates artificially high.

It’d be better for taxpayers if the city did not collect all this extra money in the first place. If budget makers did their jobs properly and developed a reasonable estimate of likely tax revenues, the surplus would not account for such a large chunk of the city’s actual budget.

Mr. Bloomberg rightly warns that these numbers can swing into negative territory in an instant – as he experienced during his first months in office. And Albany’s irresponsible sweetening of public pensions in recent years only increases the likelihood those alleged future deficits will truly occur.

City Council leaders celebrated when Mr. Bloomberg added $53 million in funding for libraries, summer jobs, and trash collection to the permanent budget. But that represents just 1% of total city spending, hardly a major concession for a mayor to make – especially for programs that make so much sense.

But spending our money well is only part of government’s job. Limiting tax collection what is really needed is also part of the deal. At least part of a fair deal.