There is a theory among some historians of the Second World War that, if only the Allies had declared war on Germany to defend Czechoslovakia in 1938, Nazism could have been defeated in a short European war.

After all, the Czech army was fully mobilised in 1938; three out of the nine panzer divisions that invaded the low countries in 1940 were to be equipped at the Skoda works in Pilsen; and revisionist historians now explain Germany's successful blitzkrieg operation before Dunkirk as the result of French blunders and defiant anarchistic gestures by German tank commanders, not genius.

So, over Christmas, I decided to test this out on the geekiest computer game known to man, Hearts of Iron III, in which you can play any nation (including if you so desire Panama) right the way through from 1936 to the outbreak of the Cold War, modelling not just fighting, not just production and research, but also diplomacy, intelligence and internal politics.

I elected to play as France and my strategy was to re-arm as quickly as possible, intervene on the Republican side in the Spanish Civil War, sign a defence pact not just with Poland but also the Czechs - and attack Germany through the Netherlands at the slightest provocation, probably sometime around 1938.

But it wouldn't let me.

My population's "neutrality" was too high and the popularity of my ruling party, the Radicals, too low. So my tanks had to rev their engines in Toulouse, failing to speed to the aid of Barcelona; then they had to mass impotently while Germany re-occupied the Rhineland, then sit through the Anschluss, Munich and the annexation of the whole of Czechoslovakia, suffering a further indignity on the outbreak of hostilities in early 1939 because the Belgians refused my request for transit rights.

At first I thought this was a pretty unforgiveable glitch. But digging into the rules, hacks and kluges of HoI3, and real life history, the game is frighteningly accurate.

Firing up the "Politics" interface I was at first amused to find my president, Albert Lebrun, classified as "barking buffoon", prime minister Albert Sarraut as a "happy amateur" and my intel boss as a "dismal enigma" - but not amused to find that I could not change any of this before the scheduled election in 1940. My finger itched over the military coup button, and I immediately resorted to installing a far-right French police chief to quell dissent and abolish strikes.

But it was not ultimately the politics that defeated my cunning plan: it was the French people - and for that matter the Brits and Americans - and their "neutrality". My neutrality score remained stubbornly high - and in that the game is superbly realistic.

For it is a fact, easy to forget amid numerous onscreen portrayals of the 1930s set in aristocratic drawing rooms, that the majority of the people in democratic countries, for the majority of the time, were opposed to war in the 1930s. As Martin Gilbert wrote:

"At bottom, the old appeasement was a mood of hope, Victorian in its optimism, Burkean in its belief that societies evolved from bad to good and that progress could only be for the better. The new appeasement was a mood of fear, Hobbesian in its insistence upon swallowing the bad in order to preserve some remnant of the good, pessimistic in its belief that Nazism was there to stay and, however horrible it might be, should be accepted as a way of life with which Britain ought to deal."

According to this view, the "Guilty Men" so expertly excoriated in Michael Foot's 1940 pamphlet may indeed have been buffoons, and lied and blundered their way through numerous decision points, but at the end of the day there was no popular clamour for war - even in fact, as the French then found out to their cost, once it started.

And I'm finding out why: it goes badly.

After several false starts I have mastered the diplomacy system and got from 1936 to 1939 without bothering to save the Spanish Republic, Austria or Czechoslovakia. I have built an expanded Allies side including Sweden, Denmark, Finland and Norway, and pushed the Swiss from neutrality to mobilisation.

The Allies have become so fearsome that, despite massing its troops on the Polish border, Germany has hesitated to make the first move but then Finland - whose politics screen I have neglected to check up on but turn out to be dodgy - has attacked Germany in March 1939 and provoked the war. Meanwhile a lot of my tanks are still being built, apparently by guys taking a lot of Gauloises breaks.

Denmark has been rolled up in a few days, the Dutch and Belgian armies are refusing to make any moves that co-ordinate with mine and I am now pushed back to the French border with - as General Weygand put it to Churchill in real life - "aucune" strategic reserve.

The Brits have had the decency to send an expeditionary force commanded by Lord Baird of Stonehaven: it consists of his Corps HQ and refuses to move from the not very useful position of Cherbourg. The Americans are having none of lend-lease and will not sell me so much as a jeep and the Soviet Union is wedded, as in reality, to the Molotov-Ribbentrop Pact.

It is me, in other words, who is the buffoon. The game is trying to tell me that if the Allies had adopted re-armament earlier, with all the military rhetoric and sentimental songs and propaganda films that would have gone with it, Russia may have cemented its alliance with Germany much earlier than in real life, and American neutrality - never fragile when it came to wars in Europe - may have been strengthened.

I draw several lessons from HoI3. First, as with all god-games, how merciless strategy is towards tactics, human beings and trivial situations. I've been is several slightly chaotic situations as a journalist and the lesson of this top-down, realtime history game is clear: you never know what's going on when it's going on.

The second is quite topical: if you want to take a democracy to war, unless your country is actually being attacked, you have to relentlessly shape the narrative. This holds true in other times and theatres than 1930s Europe.

Finally, the 1930s were a complex reality. I've studied the period a lot on and off over the years and I'm dissatisfied at the simplistic picture that's being created around it in recent TV dramas and movies, in which everybody is either fascist or anti-fascist, the war is always inevitable, and in which the focus is always the beleaguered aristocracy (King's Speech, Upstairs Downstairs) or the fascist-friendly elite (Coco Before Chanel). The drama of the time - from Odets' "Awake and Sing" to Coward's soap-like "This Happy Breed" - was always a lot more focused on real people and the real situation. Even a serial like Granada's "Family at War" (1970-72), written as it was by people who actually remembered the time, captured the complexities in a way we now seem unable to. And so in a way, and despite its ludicrous title, does Hearts of Iron.

Sartre's trilogy Roads to Freedom (also if I remember rightly turned into a drama series in the 70s) begins with a scene of a French professor wracked with guilt over his failure and inability to go to Spain and participate in the war there. As I click and drag my hapless French divisions légère (all too légère mate, as it turns out), I think I suddenly understand that whole time and atmosphere a lot better.

So I think - if we are now tweaking the school curriculum slightly back in the direction of battles and leaders - it might be worth giving a group of sixth formers a go at doing this as a project. It would certainly add the their understanding of the historical origins of "kettling".

