Political decision-making

The National Interest.
Politicians are supposed to generally act “in the national interest”, though how that is defined can depend on whether you take a long or short term view of national and international politics. But more likely on your own political outlook - so one man‘s “national interest“ can be another man‘s “unconscionable betrayal“.

Hindsight
The gift of 20:20 hindsight is granted by the Gods to those “hurlers on the ditch” who don’t actually have to make difficult decisions, which must often be taken in moments of crisis and on the basis of imperfect information (ref Rumsfeld‘s famous quote). The media, pubs and taxis are full of such “hurlers” who generally claim “I told you so”, regardless of how many changing opinions they may have offered on the topic under discussion.

So, what would happen if you could give politicians the benefit of hindsight as they take momentous decisions?

"Britain's national interest" was Neville Chamberlain’s justification for signing the 1938 Munich Agreement which betrayed Czechoslovakia to the Germans. Yet the same man declared war on Germany in September 1939 when the Germans ignored the Anglo-French ultimatum to withdraw their troops from Poland.

If our “20:20 hindsight man” could have taken Chamberlain aside and shown him the outcome of WWII, how then would he have acted?

He’d have seen that
(a) Britain and it’s allies would eventually win the war
(b) that it would develop into a worldwide conflict, with over 50m killed and many millions more injured, wounded, displaced
(c) that Hitler's domination of eastern Europe would be exchanged for Stalin's domination of the same territory
(d) that a financially bankrupt and militarily exhausted Britain would be unable to retain control of her worldwide Empire, which would disintegrate over the following 20 years, starting in 1947 with India, “the jewel in the crown”.

Would Chamberlain’s government have made the same decision in 1939 in light of this information? What would have best served Britain’s “national interest”?

Presumably if Hitler had been offered the same hindsight, he'd have promptly withdrawn from Poland and been satisfied, at least for a while, with his empire of Germany, Austria & Czechoslovakia. With fellow fascists still in power, Mussolini in Italy and Franco in Spain, how would European politics have developed over the past seven decades?

Would there now be a statue of Oswald Mosley, 1st Duke of Oxbridge and former prime minister, adorning Westminster's College Green?