The need for popularity, the need to hand the masses their happy fictions so as to maintain your own exalted and safe position amongst the political elite, aka Chamberlain's overwhelming popularity in 1938, will be the demise of western democracy as a governing concept. And that demise will result in a devastating dark age.
Easier to let it happen than to stop it. And if Russian and North Sea oil triples in price as a consequence, well, that's a bad thing for the consumers and a good thing for the sellers. And China has been very, very friendly with Iran with just that in mind.