Joseph E. Stiglitz

is a Nobel laureate in economics. He was chairman of the Council of Economic Advisers under President Bill Clinton and chief economist and senior vice president at the World Bank.

March 19 marks the fifth anniversary of the U.S.-led invasion of Iraq. It's time to take stock of what has happened. In our book,

The Three Trillion Dollar War,

Harvard's Linda Bilmes and I estimate the economic cost of the war to the United States at $3 trillion, and the costs to the rest of the world to be an additional $3 trillion - far higher than the estimates the Bush administration gave before the war.

That administration said the war would cost $50 billion. The United States now spends that amount in Iraq every

three months

. To put that number in context: For one-sixth of the cost of the war, this country could put its Social Security system on sound footing for more than a half-century, without cutting benefits or raising contributions.

Moreover, despite running a budget deficit, the Bush administration cut taxes for the rich as it went to war. As a result, it has had to use deficit spending - much of it financed from abroad - to pay for the war. This is the first war in U.S. history that has not demanded some sacrifice from citizens through higher taxes; instead, the entire cost is being passed on to future generations. Unless things change, the national debt - which stood at $5.7 trillion when President Bush took office - will be $2 trillion higher because of the war (in addition to the $800 billion increase under Bush before the war).

Cash accounting meant that the Bush administration focused on today's costs, not future costs, including disability and health-care expenses for returning veterans, and it has sought to obscure the war's costs as it has gone on. Veterans groups have had to use the Freedom of Information Act to find out the total number of injured - 15 times the number of fatalities. Already, 52,000 returning veterans have been diagnosed with post-traumatic stress disorder. The United States will need to provide disability compensation to an estimated 40 percent of the 1.65 million troops who already have been deployed. And, of course, the bleeding will continue as long as the war continues, with health care and disability costing more than $600 billion (in present-value terms).

Ideology and profiteering also have played roles in driving up the war's costs. The government has relied on private contractors, which have not come cheap. A Blackwater security guard can cost more than $1,000 a day, not including disability and life insurance, which are paid by the government. When unemployment rates in Iraq soared to 60 percent, hiring Iraqis would have made sense; but the contractors preferred to import cheap labor from Nepal, the Philippines and other countries.

The war has had only two winners: oil companies and defense contractors. The stock price of Halliburton Co., Vice President Cheney's old company, has soared. And even as the government turned increasingly to contractors, it reduced its oversight.

The largest cost of this mismanaged war has been borne by Iraq. Half of its doctors have been killed or have left the country, unemployment stands at 25 percent, and, five years after the war's start, Baghdad still has less than eight hours of electricity a day. Out of Iraq's total population of around 28 million, four million are displaced and two million have fled the country.

Statistical studies of death rates before and after the invasion highlight the grim reality. They suggest additional deaths in the first 40 months of the war from a low of about 450,000 - 150,000 of them violent - to 600,000.

With so many people in Iraq suffering so much in so many ways, it may seem callous to discuss the enormous economic costs to the United States. And it may seem particularly self-absorbed to focus on the economic costs to the nation, which embarked on this war in violation of international law. But the economic costs are enormous, and they go well beyond budgetary outlays.

Americans like to say that there is no such thing as a free lunch. Nor is there such a thing as a free war. The United States - and the world - will be paying the price for decades to come.

Joseph E. Stiglitz is University Professor at Columbia University.