The idea that the Allies didn’t try to assassinate Hitler is just plain wrong. They did their best to get him assassinated, supporting any such plan they heard of. For example, the July 20th, 1944 attempt was made with explosive supplied by the Allies.
The Allies generally did not send secret agents to assassinate Hitler, he was too well guarded, and why bother when there were plenty of Germans willing to try. Just give them the tools, and see if they will do the job.
A surprising one. Japan’s ambassador to Germany was Hiroshi Oshima. Oshima was a big fan of Nazism and Hitler liked Oshima in turn - as a friendly outsider, Oshima was somebody Hitler felt he could relax with. So Oshima was often invited to have long conversations with Hitler, where Hitler would outline his thoughts and his strategic plans for the war. Oshima, a general, was also allowed to make inspections in German military installations. And Oshima, like a good diplomat, would telegraph the content of all these conversations and observations back to his superiors in Tokyo. And the Americans would intercept all of these messages and decode them.
So the Allies had a great source into what Hitler was thinking.
If Allies would have assassinated Hitler, they might have found someone competent to put in charge.
nm several posts too late 
The British SOE hatched a plan to kill him with a sniper when he visited the Berghof called Operation Foxley. As mentioned above the fear of someone more competent (remember that by this point Hitler’s stubbornness had led to the destruction of an entire army at Stalingrad) was a factor in it being called off; the former corporal’s tactical interference with the plans of his generals was an asset to the Allies.
What was probably an even more important consideration was making Hitler a martyr (a concept the Nazis were no strangers to) or planting the idea that victory had been snatched away from Germany - post war Germans lamenting “If only our Fuhrer had lived, we would have triumphed!” The post war process of de-Nazification would have been far more difficult, the German people instead of seeing Hitler as a lunatic who dragged Germany to hell with him, he would have been a hero cut down in his prime. It would go down in the national psyche alongside the Treaty of Versailles.
Bumped.
PBS will air the documentary Operation Foxley: Mission - Liquidate Hitler on Feb. 21. Check local listings: Please login to see this page | American Public Television
This is a misunderstanding. The Allies did not “supply the explosives” in any sense except that the German plotters intentionally used captured Allied materials to confuse the expected investigation:
Source: https://en.wikipedia.org/wiki/Wessel_Freytag_von_Loringhoven#20_July_plot
Sorry to reply so late, just noticed this. It is unnecessary to suppose military officers in World War II needed outside help obtaining explosives.
They had Rudolph Hess.
Was Hess considered a reliable source of (valuable) information?
Admiral Canaris, for a time the head of the Abwehr , did feed the Allies some intel, but indirectly. One of his best games was sending totally incompetent agents into the USA and GB. Many of whom were turned and led to the Allies deception about D-Day.
While killing Hitler would be somewhat gratifying on some level, I’m not sure what advantage it would provide. The war would still have to be prosecuted. Hitler’s replacement, may have been more of an asset than Hitler would have been. And as was mentioned up thread, this time the allies were going to “finish the job” and ensure that allied soldiers marched through Berlin. Feelers to end the war early were not desired.
In some ways he was a better figurehead to the allies than he was to Germans.
I suspect any reluctance to support a Hitler assassination plot stemmed from concern that his death would massively rally the German people around the regime.
A similar concern was behind Jimmy Doolittle’s insistence that his 1942 Tokyo raiders avoid bombing the Imperial Palace at all costs, since the death of the Emperor supposedly would have unified the Japanese like no other event (though it’s difficult to conceive of a level of blind obedience greater than what the leadership enjoyed throughout the war).
My guess is that the Allies were pretty confused by Hess, and would have taken anything he said with a big grain of salt.
Anyway, he was captured in 1941, so by say, D-day, he couldn’t provide much info even if he wanted to.
But not remotely as confused as Hess was himself.
I’d say that the logistics of killing him was the biggest roadblock. It’s extremely difficult to plan a successful assassination, which is why most are by lone gunmen or the equivalent.
To pull it off, you have to depend on a lot of luck, and no military planner is going to depend on luck alone. Further, a long assassin often doesn’t care if they are killed, but anyone you order in does want to survive. That alone makes it difficult.
Even if the allies knew for a fact that Germany would immediately surrender if Adolf was offed, the difficulties of getting near him in the first place, let alone being able to succeed, makes it a dicey proposition.
Remember: Amateurs talk strategy; Professionals talk tactics; and Generals talk logistics. Killing Hitler is a strategy. Coming up with a plan to do it is tactics. Implementing that plan is logistics.
Speaking of Hess. Someone found an old blood sample the Brits took of Hess and tracked down some of his relatives and it’s a match.
So the old “That wasn’t Hess in Spandau Prison.” theory has been debunked.
More to the point, did he have anything illuminating to say about plans to invade the USSR a month later? It doesn’t look like it, AFAIK. Was he so far out of the loop that his flight was some mad attempt to make himself important again?
As for the OP’s initial premise, there was one “freelance” suggestion of a plan to assassinate Hitler before the war, that the British government (not surprisingly) stamped on.
One point that often gets overlooked is that the Allies war goal was NOT simply to get a victory over Germany and Japan. They wanted to be sure that both nations were ground down and thoroughly beaten, and that the government and people knew it. So one thing they didn’t want was to kill Hitler, then have someone negotiate a peace or have the country descend into civil war, because they expected to have to fight Germany again in 20-40 years if there was any peace that didn’t involve grinding to unconditional surrender or that had a ‘stabbed in the back’ angle like a civil war.
I am not disputing, but if this is so, when did it become policy - when the US got involved, or even earlier, say, June 1941, or possibly as late as June 1944?
It is a plausible retrodiction but is there proof that this was the Allies’ intent?
However the "Hess didn’t commit suicide theory’ IMHO has a little leg. I don’t understand the angle…no I don’t believe he had the goods on anyone…but it does seem a bit suspicious.
Britain and America formally declared a policy of unconditional surrender in January 1943 at the Casablanca conference. The Soviet Union was about to win back Stalingrad. I doubt if anything less than unconditional surrender had seriously been on the agenda of any of the Allied leaders, and the sense of the tide turning in the Allies’ favour would made publicly declaring it a simple formality.