A DN editorial:

Superintendent Arlene Ackerman and Mayor Nutter took the unusual step of holding a conference call yesterday to dispute reports of a cavernous $430 million budget deficit looming for the school district.

They acknowledged that the end of $234 million of federal stimulus will cause one cavern, but refused to speculate on how much bigger that hole will get.

So while we didn't learn much, that's not to say there aren't lessons here.

The first lesson? Math.

That there will be a bigger hole than $234 million is almost certain: Pensions and health-care costs have risen, teachers are getting raises, and the district starts the cycle with no big fund balance. Charters are seriously denting the district's budget, and Ackerman's intitiatives, like Imagine 2014, also cost.

We don't need advanced math classes to figure out that this could be catastrophic for a district that has been making steady progress on student achievement. That progress is a fact, but achieving it has cost money.

The leadership that Ackerman needs to assert now includes assuring us all that less money won't mean that gains will be wiped out . . . or even worse, that we'll be back to the bad old days of low achievement. That's why the next lesson is even more important than the first.

The next lesson? History.

In a bizarre, almost scary convergence, Ackerman's phone call Wednesday was on the ninth anniversary of the agreement for the state to take over the school district. At the time of the takeover, the district faced a deficit of $80 million; its budget was $1 billion.

Nine years later, the crisis is bigger: in a school budget of $3.2 billion, the deficit could exceed $400 million.

No one should draw comfort from the fact that this is now the state's problem. In fact, it's the opposite: We should be very concerned. That's because January brings a new Republican administration in Harrisburg that is not Philadelphia-friendly, and is unlikely to continue the spending patterns Gov. Rendell established, with education increases every year.

The new administration brings a strong appetite for charter schools - which, despite their merits, are a big cost driver for the district.

And if charters drain the school districts of its traditional funding, just wait until vouchers, which Governor-elect Tom Corbett supports.

There are many ways to look at vouchers, which give education dollars directly to families to spend on private schools if they choose.

Here's one way that bodes ill for the city: The state mandates vouchers. Education becomes entrepreneurial, rather than a public mandate. And the state ends up divesting itself of some of the direct responsibility for funding public education.

Part of the state takeover nine years ago included the creation of the School Reform Commission. This commission has been increasingly silent in the past 12 months. That silence extends to the budget questions, except for yesterday's guarded statement from Chairman Robert Archie that alludes to "a possible shortfall in the budget due to loss of federal stimulus funding."

This statement that could provide yet another lesson - in writing words that say nothing.

This is not the moment for the SRC to stay in the shadows. It's the moment for both the SRC and Ackerman to lead the discussion on the very real budget challenges the district faces, and how our children will be kept from having to bear most of the damage.

Follow us on Twitter and review city services on our sister site, City Howl.