Louisiana is the source of about 15 percent of U.S.-produced petroleum, much of it from the Gulf. The local refineries are critical to American infrastructure.
By all accounts, the Louisiana Offshore Oil Port, which services supertankers in the Gulf, is intact.
The river, as transport corridor, has not been lost.
~ It is not the population that is trapped in New Orleans that is of geopolitical significance: It is the population that has left and has nowhere to return to.
~ In order to operate the facilities critical to the United States, you need a workforce to do it — and that workforce is gone.
The oil fields, pipelines and ports required a skilled workforce in order to operate. That workforce requires homes.
The displacement of population is the crisis that New Orleans faces.
In a nutshell, the United States depends on The Dammed Mississippi.