Last time I checked, the population of NYC is approximately 8 million, and no one said just a suitcase bomb (i.e. high-yield nuke loaded on a barge and sailed right into the Harbor). As for the destruction it could cause, it would be worse than any single-day loss during the Civil War - if you want to compare nuclear attacks day after day for as long as the Civil War lasted, be my guest.
"Last time I checked, the population of NYC is approximately 8 million, and no one said just a suitcase bomb (i.e. high-yield nuke loaded on a barge and sailed right into the Harbor)."
So you suggest we do what exactly?