Mr. Chandrasekaran , an assistant managing editor of The Washington Post and the paper 's former Baghdad bureau chief , spent nearly two years reporting from Iraq , and in '' Imperial Life in the Emerald City '' he draws a vividly detailed portrait of the Green Zone and the Coalition Provisional Authority -LRB- which ran Iraq 's government from April 2003 to June 2004 -RRB- that becomes a metaphor for the administration 's larger failings in Iraq .