At one time having a bigger bomb than your adversary might have assured you peace through MAD, but now a small nuclear device is more likely the mode of attack. Many ways to smuggle in a suitcase through a terrorist, without a national finger print, to attack your enemy with. Your enemy would have no target for the megaton warhead atop those ICBMs.
A well planed attack like 9/11 but instead of training pilots for passenger jets, just have a team of terrorist carrying a suitcase into central park and/or every major city's center and then detonate. IMO, this is what the Bush administration feared and continues to be concerned about.
It is reported that after Dessert Storm, when Iraq was pushed out of Kuwait, the US Government was surprise at the progress of Iraq's nuclear technology. So when Saddam had kicked out the inspectors everyone assumed he had started nuclear bomb development again. The Clinton administration even expressed concerns.
Now after 9/11 we had to make sure that Saddam had not started his nuclear program. Knowing that he did not shy from using WMD's against Iran and even his own people. It was pretty much a sure bet that if he got a nuclear bomb he would not only use it on his neighbors but also against the US.
No, I don't think anyone wants to deal with many more nations with nuclear weapons.