Common endeavours

More questions ... again from radio listening. Hilary Clinton has been in talks with the Russians about missile defence and she was quoted (and no, I didn't realise I needed to copy down the quote until after it was over and gone forever in the ether - until the next bulletin at least) as saying it was a "common" interest. Hmmm - this could suggest that they are worried about a common enemy - or does it just seem that way.