Will it be done? The state has developed a “master plan” to do it. The biggest technical problem involves sediment, which has declined as much as 50 percent, giving engineers less to work with than nature had. The state hopes to distribute the sediment through pipelines or “diversions,” which are openings in levees, to replicate natural flow.

But as difficult as the engineering is, the politics are more difficult. Most experts consider diversions the only long-term land-building option, yet oystermen have already mounted a campaign against them, arguing that they will destroy oyster beds and fail to build land, while the shipping industry worries about any changes that could affect the channel.

And the fight over diversions is only a skirmish; the real fight will begin when people outside any planned protection realize their communities will disappear, or if the state adopts a proposal advanced by many experts to create a new river mouth, amputating part of the state. Already one region is angrily protesting a corps proposal that could require people to move from areas of “severe repetitive” flooding. Then of course comes the question of money. Officially, the statewide master plan will cost $50 billion. Approximately one-fifth of that would go to giving New Orleans 500-year protection. But a Tulane University study puts the actual cost for the master plan at more than $100 billion. And even at $50 billion, the state is woefully short.

The recent BP settlement provides $6.5 billion to $8.7 billion for coastal restoration. The state also gets $90 million annually from a federal program which expires in 2019. And it is counting on $170 million annually, beginning in 2017, from federal offshore oil revenue-sharing, but the Obama administration has proposed redirecting those funds.

Louisiana politicians, while decrying tax increases and demanding budget cuts, not only want to keep that federal money flowing; they also want federal taxpayers to fund the master plan. They point out that federal projects caused much of the land loss: Levees prevented natural distribution of sediment by floods, and many of those levees safeguard not populations but shipping channels. Missouri River dams protect people from Montana to St. Louis from floods but retain roughly half the missing sediment that once sustained the coast. And canals built for shipping both internationally and from Texas to Florida benefit the entire nation, while Louisiana bears the costs.

BUT the political reality is that taxpayers around the country are not going to be sending Louisiana tens of billions of dollars anytime soon, especially while Louisiana’s politicians avoid dealing with another major cause of land loss.

Oil, gas and pipeline companies have dredged an estimated 10,000 miles of canals through the coast; ensuing salt water intrusion killed plants, without whose roots land dissolved. Companies also sucked so much material from below ground that the surface sank. No one seriously disputes industry’s role in land loss. Even a study funded by the Louisiana Mid-Continent Oil and Gas Association, the trade association for major oil companies, concluded that industry operations were “the overwhelming cause” of land loss in areas where loss was most severe. A state government study attributed 76 percent of land loss in those same areas to energy companies. A United States Geological Survey-led study, which included industry scientists, attributed 36 percent of the loss across a larger section of the coast to the industry.