I think you gents are being deliberately simplistic, but that doesn't help me who wants to learn. I've been listening to public radio so I know I've heard something worthwhile.........(;-)).

Anyhoo:
1) From the Extreme Left: Anti-Globalization, fear of cheap labor.
2) From the middle: Resentment at the existing unelected bureacracy and fear of an even worse one ahead; Resentment at local political leaders (not directly related to the vote); Resistance to adopting such a dense and unromantic document as a 'constitution'.
3) From the Extreme Right: Anti-Globalization, fear of foreign immigration and increasing multi-culturalism. Hope that this decreases Turkey's chance of joining.

Overall outlook: This might appear to be mildly beneficial to the US on a selfish trade-barrier basis, but in reality it is overall perceived as a weakness of "The West" in an age where there are significant forces in play to further weaken "The West." So in the broader view and over the long term, this is not good for the US.

For UK I suspect the same as for the US. The UK is supposed to be voting on the Constitution later. I'm not up on the polls.

Comments invited!