WASHINGTON -- Any attempt by Senate Democrats to revoke the 2002 congressional resolution authorizing the war in Iraq and to restrict U.S. troops to a limited mission as they prepared to withdraw faces a fight, a White House spokesman said Friday.

Tony Fratto also suggested that the Democrats weren't sure exactly what legislation they want, and what it might mean on the ground in Iraq.

"I think what's clear is that there's a lot of shifting sands in the Democrats' positions right now. It's hard to say exactly what their position is," he told reporters.

In addition to the measure revoking war authorization, Fratto said, "There are those who want to strictly cut off funding, there are those who want to do things like find backdoor ways to keep troops from circulating into Iraq."

If there are efforts to pull troops from Baghdad, there are consequences for Baghdad, Fratto said, citing recent National Intelligence Estimates.

"It would bring chaos to Baghdad," he said.

The Bush administration has argued that changes in the war resolution were unnecessary even though it was drafted in the days when Saddam Hussein was in power and there was an assumption -- later proved false -- that Iraq possessed weapons of mass destruction.

"We think the resolution that is in place is operative and that's where we are right now," he said.