You have your facts wrong.

Firstly, there were German and Japanese spies, but there was basically nobody on the Allied side who thought it was whistleblowing to leak secrets to Hitler. Unlike the case of the Soviet Union, which the Manhattan scientists did think it was whistleblowing, and did leak the nuclear bomb secrets, Wikileaks or no. Also unlike the case of the German military, which was riddled with anti-Hitler resistance who leaked what they could to the Allies, again Wikileaks or no. So if Wikileaks existed in 1940, it would have made easier the life of Schulze-Boysen acting against Hitler, not Bomber Harris acting against Churchill.

Example references:

http://en.wikipedia.org/wiki/Klaus_Fuchs

http://en.wikipedia.org/wiki/Wilhelm_Canaris

The French Resistance was useless. Besides, traitors amongst them could easily have dropped off an anonymous tip to the Gestapo or even turned double agent. Wikileaks would have been a lot less decisive in this case.

Finally, the Germans already had lots of evidence about their enigma code being broken, and about the British radar system. Hitler himself told the generals the attack would come at Normandy.

However, the German generals could not bring themselves to believe it. They had too much hubris to believe that their codes had been cracked. And they could not believe that the British would use such shitty old fashioned radar. The German counter measures were designed to work against good radars such as their own, and no one had thought of building counter measures against the British crap. This gave British airpower the advantage. Sadly I don't have references on me for these, but I do have a reference for the Normandy landings.

The German generals refused to believe Hitler because landing at Normandy would be insanely expensive in Allied blood. Only a complete idiot would decide to land at Normandy. The fact that Hitler told the generals is made a point of in Shirer's book:

http://www.amazon.com/Rise-Fall-Third-Reich-History/dp/14516...

So World War 2 is a really lousy example for you to use.

Besides, to protect against this sort of thing, Wikileaks have a disclosure policy. For example, when they released the diplomatic cables, they tried to go through the newspapers first: anything the newspapers redacted, they redacted too.

Secretary of Defense Robert Gates admitted that "the review to date has not revealed any sensitive intelligence sources and methods compromised by this disclosure" and later stated "Is this embarrassing? Yes. Is it awkward? Yes. Consequences for U.S. foreign policy? I think fairly modest."

References:

http://www.telegraph.co.uk/news/worldnews/northamerica/usa/8...

http://en.wikipedia.org/wiki/WikiLeaks

So frankly, Wikileaks are mitigating your fictitious Hitler-in-1940 scenario anyway. And I trust them way more than I trust the politicians telling me what I don't need to know.

>The theory has a lot of vocal opponents, but Suvorov never misses a chance to point out that most of them are (paid by) Soviet political/military figures, who are obviously biased and would never admit such a plan.

Highly recommend "Rise and Fall of the Third Reich", the work which is almost academic in quality, if not in shape :

http://www.amazon.com/Rise-Fall-Third-Reich-History/dp/06717...