"We believe that a four home unions bid would make a compelling proposition for world rugby, " said McKee.

BBC: Scots look to co-host World Cup

Scottish Rugby Union chief executive Gordon McKie said a bid involving England, Scotland, Ireland and Wales would be "a compelling proposition for world rugby".

BBC: England weigh up 2015 bid options

Now, as people around the world intone the proposition that the United States is the world's only superpower, it is therefore tempted to pursue foreign-policy goals all by itself.

ECONOMIST: The many-handed Mr Eizenstat