Most people who know about the history of World War II would be aware that Colonel Claus von Stauffenberg was something of a hero. There are even memorials to him and his fellow conspirators in today's Germany, and are in fact, the country's only World War II veterans to whom this has been done. However, his story has not been one that filmmakers have exactly been tripping over one another to fulfill the desire of translating it on to the screen. He was at once treacherous and noble - he tried to murder his leader Adolf Hitler. Treachery in a humane cause can be a noble thing and any educated child would, I hope, be able to tell you that Stauffenberg must have failed because a bombing at Wolf's Lair is not how Hitler 
died.  So obviously the story of Stauffenberg is a story of failure and the outcome has to be a slight downer.

Tom Cruise’s pretty-boy looks and action hero roles have done a lot for him, but 
now they are working against him here. Stauffenberg himself did 
not exactly possess matinee idol features but Cruise's interpretation of Stauffenberg isn't entirely inaccurate. Claus von Stauffenberg determines that Adolf Hitler is leading Germany to destruction. The film (and history) are a little unclear on Stauffenberg's exact motives.  Hitler really was destroying Germany, and Germany was 
going to suffer for his terrible leadership. Mentioned also is Stauffenberg's indignation at the inhumane offences being perpetrated by Germany. One set of motives is practical and selfish, the other motivation is on a slightly higher level. In any case, Stauffenberg determines that action must be taken to remove the Fuhrer from power, this in a society where disloyalty was a capital 
crime.

Early on in the film Stauffenberg seems a little too open about his
opinions, but loses some of his over-confidence when his heroics badly maim and almost kill him in a battle in Tunisia. Returning to Germany he continues his campaign to remove Hitler, 
though a little more discreetly than he did in the field.  He finds others willing to join the plot against Hitler, in fact, one apparent expedient of the script is that he finds like-minded people just a little too easily and he seems all too ready to put his life into other people's hands.  Obviously a very dangerous practice, as Stauffenberg had to survive on more than one occasion, putting his own safety and fate into the hands of strangers.  It seems from the dramatisation that to varying degrees just about anybody he takes 
into his confidence is willing in one way or another to 
co-operate, even if it is just willingness to omit reporting these acts of treason through such treacherous conversations, as the plan progresses to the assassination attempt and its tense aftermath.

Scriptwriters Christopher McQuarrie and Nathan Alexander have done 
a surprisingly good job. Too frequently "political 
thrillers" turn out to be mostly gunfights and car chases.  There is one battle scene and one short gunfight, but for the most part the tension comes from the dialogue and plot. Words are traded, but rarely bullets.  

It is rather ironic that the producers are making a story of a man who failed and in a good cause brought about disaster on his co-conspirators. Had he remained to make sure the bomb killed Hitler, history would have been quite different.  Had he been willing to die in the effort, he might actually have been a 
success. This is a high-tension thriller that that survives the 
fact that much of the audience knows how everything turns out.  

It is fascinating to speculate how the world might have been different had the plot succeeded. Had Germany capitulated for peace in July or August, 1944, the Soviets would have had much less of a foothold in Eastern Europe. That part of Europe would have been
much more like Western Europe and Germany would have escaped a great 
deal of the destruction that came in the remainder of the war. 
Rebuilding Germany would not have been as necessary as the country would not have the modern atmosphere that it does today and might be a good deal less forward-looking.  After August the Pacific War would have gone a great deal faster, having the full wartime resources of 
the United States. This would have brought American troops to the shores of Japan before the nuclear weapon was ready. The only other alternative would probably have been the invasion of Japan, and as they (the Japanese) were ferocious fighters on the small islands of the Pacific they would have been really terrifying defenders of their homeland, trained to die rather than lost honour by surrendering. 
The cost in lives might easily have been over a million with each side taking very large hits. The Allies had greater access to 
resources so Japan probably would have eventually lost, but it is unclear what would have been left of their country when they did. 
This would have left lasting hatred on both sides. The resulting future of nuclear weapons is very unclear and they may well have been used on Japan eventually anyway, and it probably would have leaked to the Soviet Union in much the way that it did. This is all just speculation but the UK, Germany, Japan, and the United States might all have been considerably worse off in the remainder of the 20th Century.