However, how can you justify a retaliatory strike against, say, Damascus, when you still aren't sure who set one off, even if it's a major city? A ballistic missile can be back-tracked on radar, you can see where it came from. Most terrorism scenario's have the weapon smuggled in, hidden in the target, and then set off.(BTW, a Thermonuclear explosion makes' it hard to collect evidence as to whodunnit.)
It's real EASY if someone in the government has the stones to put it all out on the table. Our policy should be this. Any country that is involved with nuclear programs not under UN inspections WILL have their capital cities destroyed by thermo nuclear devices in the event of a nuclear attack, i.e. North Korea, Syria, Iran right off the bat. If it is detiremined that the marterial used was obtained from anouther country, they're next.
By the way even after a thermo nuclear blast, with a few dust sized particals of radioactive material, you CAN determine exactly where the nuclear marterial came from. The ratio of nuclear isotopes vary from reactor to reactor where it was created. Nuclear scientists can even narrow it down to what part of the reactor it came from. I've had this conversation with my best friends brother who is a nuclear engineer with a Phd in nuclear pyhsics. He is a nuclear power plant manager in Ohio and he knows what he's talking about.
With terrorists you might not be able to find out who dunnit, but you can damn sure find out who provided it, and with stakes that big, that makes them just as guilty.