Can a nukes radiation take out the united states with one bomb?

Question

Can a nukes radiation take out the united states with one bomb?

Answer 1

a thermonuclear warhead can destroy a capitol city, also had capacity for kill millions and collapse the every kind electronic devices,inc.data bases ( only Faraday circuits can protect the electronics ) at more than 100mile+  length circle with electro magnetic pulse ( EMP )  

That kind of hit definitely pollute the land - water and earth with radioactive waste for generations .. but wiped out a entire continent? nope .. can't.

Mostly powerful bomb who build by mankind was craft by Russians at early 60's.

If I remember right Russians use "Ivan" codename for that bomb ( like Ivan The Terrible )  this big guy was really powerful ( 100megaton ~ 3.500 time powerful then Hiroshima's ) and heavy ( 27 ton ) but even Ivan the terrible can't do that this by solo.

Answer 2

no the blast could take out an entire city.  the radiation would take out the entire county and maybe some surrounding areas

Answer 3

A nuke may not, but an EM (electro-magnetic) bomb could. With most machinery and communications down, the States would be easy pickings.