How should the U.S. respond to a terrorist group that causes a nuclear detonation on U.S. soil?

Question

In the future, a nuclear device may detonate within the continental U.S., and a terrorist group may take credit for the blast. Assume a cell-based terrorist organization that exists within the borders of more than one country.
1) Describe the appropriate military response.
2) Describe the appropriate legislative response to "increase national security" if you feel the strike would warrant new policies.

Note: After reading some initial responses I would like to clarify two points:
1) A cell-based terrorist organization cannot be eliminated through a declaration of war. The information is compartmentalized to prevent destruction of the whole through capture of a part.
2) Modern terrorist organizations operate beyond "home-country" borders. Elimination of a "home country" leaves the "out-of-country" cells in operation, and possibly puts "fail-safe" or "last-ditch" plans into operation.

Answer 1

Why do you think the West is so concerned about Iran and North Korea? The former has a nuclear program and the latter already has nuclear weapons technology.

Any of the two country would be possible source of WMDs and should a terror group gets one to detonate within the US it would be catastrophic. The persons/group responsible may be from several countries, some of them friendly to the US. Which means the US cannot respond by nuking the countries.

What was the US response to the non-nuclear 9/11? The sacking of Afghanistan and Iraq country leaderships even though terrorists were from Saudi Arabia, Jordan, Morocco etc - there were no known Iraqi or Afghan terrorist.

Military force is futile in fighting terrorism because for every leader killed, dozens more can serve as replacements. Terror groups, insurgents, militias fight guerilla wars which are near impossible to wipe out (still fighting in Iraq, Afghanistan).

The USSR gave up after a decade of fighting tribesmen in Afghanistan; the might of half a million US armed forces gave up to the Vietcongs after more than a decade. Muslim elements in Indonesia were recently reported to have asked their government to sent them to Lebanon to join their fellow muslim brethens to fight the Israelis.

Former PM of Malaysia recently called upon Iran, Syria and others to fight the US-UK-Israel axis as enjoined in the Quran.

The brotherhood of muslims (more than 1 billion worldwide) is rich recruiting ground for fighters. No military force on earth can hope to eradicate this 'army'.

The US is geographically blessed - none of the major conflicts: WW1, WW2 affected Americans at home in the mainland - in the unlikely event of an isolated nuclear explosion on American soil, the US may go after the rogue country that sponsor terrorism - proof or no proof.

Answer 2

If such should occur, the obvious answer would be to determine the guilty party. If it should have come from North Korea, we would need to determine the effect of a nuclear response on China and then their response. Showering a nation with nuclear weapons is both stupid and self-destructive as the environment can not endure with a major exchange. You are drinking milk today that has been contaminated by nuclear tests and Chernobyl...and carcinogens are increasing with pollution without more additions. Legislative actions are both inappropriate and closing the barn door after the horse ran away. Everything must be done at the moment, we can't use prescience or deja vu as a safe-guard.

Answer 3

Total annihilation of the terrorist organization and of the country harboring and aiding the terrorist's. Probably no need to nuke them as we can pretty much do the job thoroughly without the nukes
No new legislation is needed. Just an immediate declaration of war

Answer 4

what ever country sponsored it and the home country of those who did it.10 nukes on there 10 largest city's. Any terrorist would know if he does it to US his country pays.They want terror I say give it back 10 fold.If Israel would carpet bomb a Hezbollah (10) site for every rocket they launch this would end in 5 days.