This year’s battle over Iraq war funding officially kicked off Wednesday as Defense Secretary Robert Gates reluctantly offered a price tag for the first time: $170 billion for fiscal 2009.

Speaking at a Senate Armed Services Committee hearing, Gates only gave the number after Chairman Carl Levin (D-Mich.) pressed him, but rejected his own estimate right off the bat, calling it a number that “will inevitably be wrong, and perhaps significantly so.”

Levin insisted that he give his best estimate for next year’s war-funding needs.

“Well, a straight-line projection, Mr. Chairman, of our current expenditures would probably put the full-year cost, in a strictly arithmetic approach, at about $170 billion,” Gates responded.

Lawmakers have been upset with the administration for not providing a complete estimate, as required by law, for how much the wars in Iraq and Afghanistan will cost next year. Instead, the Pentagon asked this week for a $70 billion “bridge-fund” without offering details on what that request would entail. 

Gates has also pressed Congress in recent days to pass the remaining $102 billion from the fiscal 2008 war supplemental request, arguing that the financial uncertainty of this year makes it hard to project what the military will need next year.

“While the monetary cost is not the most important part of the debate over Iraq or Afghanistan, it does need to be part of that debate, and the citizens of our nation have a right to know what those costs are projected to be,” Levin said.

With the estimated $170 billion for fiscal 2009 and the remaining $102 billion from this year’s supplemental, the cost of war operations could reach $1 trillion by the end of fiscal 2009. Congress has appropriated $691 billion for the wars since 2001.

Other Senate Democrats expressed frustration over the administration’s tactic of not submitting the entire request and were cool to Gates’s estimate.

“He can suggest whatever he needs and we’ll weigh it,” said Senate Majority Leader Harry Reid (D-Nev.) “Right now we have enough money to run everything until June, we were told yesterday, so I’m not going to worry about it for a while.

“I guess they need a little bit more practice on how to get the numbers right for the war’s cost,” Reid added. “It’s only been going on for five years.”