With no control group, none of the individual causes is either proven or disproven. Assigning culpability then becomes a matter of political opinion and, usually, prejudice.
There is more than enough blame to go around; finding that Boris Johnson is a corrupt dilettante who collects political offices for the same reasons, and with the same casual disregard for the consequences, as he collects mistresses in no way detracts from the fact that Gordon Brown was an arrogant half-wit.
With no control group, none of the individual causes is either proven or disproven. Assigning culpability then becomes a matter of political opinion and, usually, prejudice.
There is more than enough blame to go around; finding that Boris Johnson is a corrupt dilettante who collects political offices for the same reasons, and with the same casual disregard for the consequences, as he collects mistresses in no way detracts from the fact that Gordon Brown was an arrogant half-wit.