UN Security Council Reform in 2012 - looking ahead as far as 2050 (2010 edition)

[Furunculus]

I think what I picked #3 is the most likely to occur aside from Mexico being there and the EU instead of France and the UK separately.

I'd prefer that it be by GDP, ability to send expeditionary forces (the SC members would also be the enforcers ), as well as be a country that allows at least elections for the head of the government (in order to let the UK keep a seat) with free open, multi-party elections (I'd hope that by 2050 the PRC meets that requirement).

Once again I can't really see France or the UK giving up their seats to a EU power. The UK for reasons of past greatness and idea that they like being not entirely hemmed into the EU. As for France, I couldn't imagine it giving up it's seat to an EU that could very well be dominated by the Germans.

China is the only sitting permanent member that would want power by population so I doubt the others would give in to that.

oddly enough, looking at those Caregie projections I find it less and less likely that the UK will have to give up its seat for the following reasons:
1. the UNSC is going to expand from five, probably to nine at a minimum
2. the UK will still have the 7th largest economy in GDP terms
3. the UK will have the 9th largest economy in GDP (PPP) terms
4. the UK will have the largest economy in the EU by 2030
5. the UK will have the largest population in the UK in a similar timeframe (turkey withstanding)

my guess is biggest nine or the rotation idea of the fourth option.

I also agree that expeditionary forces are going to weigh very heavily in the deliberations, and the second most capable expeditionary force in the world is, and i likely to remain, the UK.