While it looked like the operation might well succeed, it did not. A bomb that Stauffenberg took to a meeting where Hitler was supposed to be went off, and even injured Hitler and killed four officers. However, Stauffenberg was identified, and many of his associates were located. After a very brief trial, many were executed and buried in a mass grave. Hitler was so outraged that he used his policy of Sippenhaft (or "family punishment") to round up family members of the conspirators. The the mothers and older offspring were interrogated and sent to labor camps, and the children were taken from their homes, cared for by nannies, and eventually sent to a youth retreat called Borntal. There, their names were changed, and while their basic needs were met, they suffered a great deal of psychological trauma.
It is hard to comprehend how devastating World War II was to the German citizens. Yes, many of them supported Hitler and his radical policies, but many were just trying to survive. I found the after note about how the history of the war was taught in German schools to be very interesting. It wasn't until much later that the people involved in the coup attempt were treated as heroes. Ensnared in the Wolf's Lair is an excellent book showing the personal cost that a group of conscientious citizens paid in trying to wrest their government back from the hands of extremists.