How exactly can you tell what is and is not Divine Intervention?
The will of God is hard to explain. If I had a PhD in Theology and focused on that only, I might have something intelligent to say...
Before I get knee deep in a subject about God's will, I have to preface the discussion that I have seen many things in my life that are not explainable except by the Supernatural (God and the world of spirits -- good and evil).
In the case of the Wolf's Lair bomb-blast, Hitler was severely wounded. Rommel (the Desert Fox) was part of the plot to kill Hitler (and died for being part of the plot).
If Hitler had been killed, it is possible someone sane may have taken over Germany and killed more Americans, British and Russians.
The timing of the Wolf's Lair attempt on Hitler's life was around the time of the Normandy invasion (after it as I recall) but before the Battle of the Bulge.
The Battle of the Bulge helped to shorten the war -- Hitler used all of Germany's manpower reserves in this insane attempt to split the Allied front in the West. This may have saved many lives by Germany having many soldiers captured in the Battle of the Bulge. And it may have saved the lives of many in Concentration Camps [the war being shortened]. Finally, by shortening the war in Europe, it may have saved many Allied lives and Allied soldiers from being wounded.
Everbody agrees Hitler was a madman -- and his crazy ideas probably help end the war quicker.
As for President Bush, many people pray for him. So it is reasonable to believe God may have not only protected him but also the Secret Service (who would have been more likely to have been injured).
What you are talking about is more about God's will than anything else. And that is a heavy subject. Why did so many Americans die in the Civil War battles of Shiloh Meeting House and Gettysburg? Why did the weather turn in the favor of the Allies on D-Day (the 6th of June 1944)? Why did the United States win the all-important battle of Midway by a just a few planes in the right place at the right time?
When you die you can ask God the question. If you are in heaven for all eternity, it may be a trivial matter. And after ten or twenty thousand years, you might have a complete understanding.