WASHINGTON  At the outset of the Iraq war, the Bush administration predicted that it would cost $50 billion to $60 billion to oust Saddam Hussein, restore order and install a new government.

Five years in, the Pentagon tags the cost of the Iraq war at roughly $600 billion and counting. Joseph E. Stiglitz, a Nobel Prize-winning economist and critic of the war, pegs the long-term cost at more than $4 trillion. The Congressional Budget Office and other analysts say that $1 trillion to $2 trillion is more realistic, depending on troop levels and on how long the American occupation continues.

Among economists and policymakers, the question of how to tally the cost of the war is a matter of hot dispute. And the costs continue to climb.

Congressional Democrats fiercely criticize the White House over war expenditures. But it is virtually certain that the Democrats will provide tens of billions more in a military spending bill next month. Some Democrats are even arguing against attaching strings, like a deadline for withdrawal, saying the tactic will fail as it has in the past.