The Israelis recently bombed a target of some sort in Syria. It was a unique situation, because the Syrians didn't complain about it other than mentioning a violation of their airspace. Now we know why. They didn't say anything because the Israelis caught them with North Korean nuclear materials.
There are many things I can tolerate rogue states doing. Proliferating nuclear materials isn't one of them. A really big red line was just crossed.
In a related subject, what of the prospect of a dirty bomb attack on an American city? Imagine: a small explosion in New York or Chicago. Suddenly some Joe with a Geiger counter calls up the media and tells them that the readings are off the charts in the proximity of the explosion. Word spreads that the bomb was nuclear, and that a radiation cloud is engulfing the city. Citizens panic and rush to evacuate. There are mass casualties in the chaos, with destruction and violence on a large scale. Imagine Katrina, only worse, and in a bigger city.
This is why our government should have a strong public awareness project concerning dirty bombs. Humans can take a lot more radiation than we do now without having any huge problems. If there was a dirty bomb attack, unless someone purposefully went to the explosion site and started rolling in the bomb's remains, I can't imagine it would be a big deal. The government needs to have a containment plan, a cleanup plan, and a very clear and honest assessment of the danger. People need to understand before the fact that a dirty bomb does not merit the evacuation of an entire city - only a few blocks or so.
Terrorists don't need a nuclear bomb to do massive amounts of damage. All they need is a regular bomb with a tiny bit of radioactive material. The real power behind that weapon would not be the explosion, or the radiation - it would be the ignorance driving the chaos after the fact. People need to understand the dangers, so they won't panic when it happens.
...and given recent developments in Syria, we can assume "when" will be sooner rather than later.