As long as we are dealing with reality today, eminent domain and all, why not just open both eyes. One nuke [depending on yield, Hiroshima-sized being not so serious] would be disastrous, but the country would cope. Three nukes of 200 kton or more in the wrong places would ruin the country for decades. Any more than that would ruin it for a century.
The same for any other country.
Just a thought... we busted a LOT of nukes right here during the `50's and we are still here. 97 to be exact. We could recover from a terrorest attack involving multiple locations, even urban locations.
"The United States conducted 119 nuclear tests at the NTS from the start of testing in January 1951 through October 1958. Most of those nuclear tests were carried out in the atmosphere. Some tests were positioned for firing by airdrop, but metal towers were used for many Nevada tests at heights ranging from 100 to 700 feet (30-200 meters) above the ground surface. In 1957 and 1958, helium-filled balloons, tethered to precise heights and locations 340 to 1,500 feet (105 to 500 meters) above ground, provided a simpler, quicker, and less expensive method for the testing of many experimental devices. The tests of the atmospheric era took place in Yucca and Frenchman Flats. The 119 nuclear tests that were conducted at the NTS during the atmospheric testing era (1951-1958) consist of 97 nuclear tests conducted in the atmosphere, of two cratering tests, detonated at depths less than 100 feet (30 meters), and of 20 underground tests."
http://www.fas.org/nuke/guide/usa/facility/nts.htm