WASHINGTON The leaders of a Senate panel said Thursday that the US Defense and State departments must work more closely together to avoid repeating multimillion dollar mistakes in the reconstruction of Iraq. Sen. Joseph Lieberman, chairman of the Homeland Security Committee, and Sen. Susan Collins, a Republican, said they were considering legislation to create a commission to help fix problems after investigators found confusion and disarray in the four-year-old reconstruction effort. "Where we've seen failure is when the US government failed to plan projects carefully and then failed to keep a close watch over contractors and now we've seen billions of dollars wasted - a cost measured not just in dollars but in the undermining of the overall US mission in these war-torn countries," said Lieberman, an independent who votes with the Democrats. Stuart Bowen Jr., the special inspector general for Iraq reconstruction, released his latest report on the lessons learned in a war and reconstruction effort that has cost taxpayers nearly $400 billion. It detailed a series of mistakes, delays and missed opportunities. Characterizing the US effort as chaotic and poorly managed, Bowen found numerous problems - from a lack of strategy and unclear lines of authority to confusion and disarray between Defense and State.