It’s kind of galling to allow now, in 2008, that von Stauffenberg et al were either totally unaware of this, or that they felt their mission superceded it. In “Valkyrie,” at the expense of making a joke, they are almost like Franz Liebkin, author of Mel Brooks’s fictitious “Springtime for Hitler.” His famous line in “The Producers” is: “War? What war? We vas in the back. We didn’t see a thing!”
A good list of Hitler assassination attempts is here, some by people less reprobate. Many involved in the German resistance were less bloody-handed than von Stauffenberg: for example the leader of the anti-anti-Semitic Confessing Church in Germany, Dietrich Bonhoeffer, hanged with piano wire during the post-Valkyrie purges, and the Weisse Rose, all beheaded by the Gestapo in '43.