All of the suggestions posted are excellent. I would also look into the failure of Stalin to heed Russian intelligence that forewarned of the
impending Nazi invasion of Russia, Operation Barbarossa
For something really underhanded, check out Operation Mincemeat
. This was a top secret
plan by the British to fool the German High Command into thinking that the Allies would be landing the bulk of their forces at Sardinia and the
Balkans, rather than the actual target, Sicily. The Allies took a corpse, dressed it in an officer's uniform, chained a briefcase to its wrist with
classified, false documents hinting at the false invasion points. Then, they placed the body in the sea where they knew it would be found and
delivered to the Nazis. The plan worked a treat. The Nazis sent many of their best units to protect the fake invasion sites of Sardinia and Corsica.
Hitler even diverted 2 crack panzer divisions away from the Eastern front to protect Greece.
In the end, Operation Mincemeat allowed for a successful invasion of Sicily, a foothold to be gained in Italy and gave the Russians more freedom to
operate in the East.
Hope this helps.
You might also want to take a quick look at the efforts of the French Resistance
resistance movements were formed in many countries, the French movement is probably the most well known. I am sure the Nazis considered their
disruption of supply lines and constant guerilla tactics to be very underhanded, but they were certainly effective.
Also consider the efforts of Juan Pujol Garcia. Juan, operating under the codename Garbo, was considered by the Germans to be one of their best spies.
In reality, he was actually a double agent working for the Allies. In 1944 he convinced the Nazi leadership that the Allied landings at Normandy under
the D-Day Operation Overlord
were merely a diversion to make way for the main landing at
Calais, further along the coast. The Nazis believed their trusted spy and the Allies were able to make the landing at Normandy with significantly less
resistance then they would have met had it not been for Garbo's deceptive efforts. Amazingly, Garbo managed to fool the Nazis so completely that he
was actually awarded their highest honour, the Iron Cross, for his efforts. Read about Juan, aka Garbo in
this article by the BBC
Again, I hope this helps you out.
[edit on 5/9/05 by Jeremiah25]