Washington ? How much would a war with Iraq cost?

Most estimates fall in the $50 billion range, though a top White House economic adviser suggested this week it could rise as high as $200 billion.

With so many uncertainties in war, the reality is that nobody knows. Still, under most scenarios, the federal budget could absorb the financial cost of waging a war without much trouble, economists say.

From an economic standpoint, what’s more worrying than the cost of invading Iraq is the potential impact of a war on the U.S. and global economies. A war could drive up the price of oil and depress consumer and business confidence. Steep oil prices and declining confidence could push today’s anemic economy into recession.

That’s unlikely to happen if a war is won quickly, as military experts expect. In fact, battlefield success could boost confidence and calm oil markets. But given the uncertainty of war, a recession can’t be ruled out.

“The U.S. is moving forward in a way that is going to drag its economy down,” said Peter Navarro, a business school economist at the University of California-Irvine.

Any war costs would add to a projected federal budget deficit of $145 billion for the next fiscal year, which begins Oct. 1. But economists aren’t concerned about the impact on the federal budget because it would be a one-time expense.

Gauging the costs, though, remains educated guesswork at best.

“It is not knowable what a war or conflict like that would cost,” Secretary of Defense Donald Rumsfeld told a congressional committee Wednesday. “You don’t know if it is going to last two days or two weeks or two months.”

Cost estimates tend to be based in part on the cost of the 1990-91 Gulf War, which came in around $60 billion, or about $80 billion in today’s dollars.

Iraq’s military is weaker than it was in 1990, so analysts believe an invasion wouldn’t require the 500,000 troops that took part in the Gulf War.