Yesterday, on the fifth anniversary of Hurricane Katrina, President Obama was in New Orleans to address a crowd at Xavier University. He assured the crowd that his administration is "working to restore protective wetlands and natural barriers that were not only damaged by Katrina… but had been rapidly disappearing for decades." Katrina and the Gulf oil spill have re-focused attention on the decades-old goal of restoring the wetlands at the mouth of the Mississippi. But so much has been eroded away by ship channels and oil pipelines that current efforts may not be enough even to maintain the status quo. Is full restoration possible? What would it cost? What would it mean for oil companies, shipping and the fishing industry?