I hate to admit that I saw this on Rachel Maddow, but she picked about 10 or so metro areas directly on the coast (something like LA, Seattle, SF, New Orleans, Jacksonville, Miami, Norfolk/Newport News, Balmer, NYC, and Boston) and pointed out 63 MM people live in those cities on the coast, or about 20% of US population. She said she skipped over Houston, Philly, Providence and Washington because they were less directly exposed even though they were on estuaries (query why Balmer then?), but those too are hurricane or tsunami exposed.
Flood insurance really needs a hard look when it comes to envcouoraging development of barrier islands, but we need ports and we can't go Cambodian and empty our cities that have ceased to function as significant ports. You do have to wonder how much of Chris Christie's we'll rebuild everything is just a gut reaction, but the Jersey shore is a heck of a resource and source of livelihood. The Lower 9th in NO is still not back, so some of this shore community destruction will not return. Maybe that makes sense economically and environmentally (don't waste money and expose lives), but it is still devastating if it ends this way for so many families. some hardening of our cities is probably feasible and needed at a high cost, and rebuilding the shore with an expectation that what you build will be flooded at some point (that is, less intense, fewer residents, less capital, and prudent investment in reconstructed dunes and seawalls) is probably the right path forward.
BTW - Has there been any talk of flood gates on the Potomac south of the city?