Against that, Unionist politicians pose two arguments: that oil revenues are volatile and that the broader tax base of the UK permits greater resilience against short-term shocks such as sharp increases in unemployment and, therefore, benefits.
At Patrol Base Wilson, in Kandahar province's volatile Zhari district, American and Canadian military trainers are trying accomplish a top-priority task, something many Afghans believe can't be done: create a police force that will maintain law and order in a country where few feel safe anymore.