If economic dependencies and the belief that we can't turn into targets only the Third World weren't enough, French and British nukes already are there to deter. (North Korea's few nukes are enough to deter.) But to build a strategic arsenal on par with that of the USA, I think that is a practical impossibility (and one realised as such) for the above wide-ranging reasons. (For example, no one will want to branch off that much money from the economy.)

As for "credible force", this is the mantra of the Euro-militarists already, but I don't see it catching on just because of the USA. The EU likes to deal with outside effects through economic and diplomatic means, and most people can't really feel all that threatened. A US nuke in Iran won't change that.

I actually think the reason that there are less resistance now, is that the great majority of people (including European politicians) think the US is bluffing

I am sceptical on that. After Iraq, I'd expect people to assume the opposite, and lack of resistance comes from a feeling of powerlessness. (The Franco-German opposition to the Iraq war gave a lot of people hope, I don't think the 15 Feb 2003 protest would have been as big if they had lurched along.) As for the politicians, I believe they unfortunately believe they can hold off the neocons with appeasement, not that they don't mean it.

_{*Lunatic*, n.
One whose delusions are out of fashion.}