Nazi Pope: not just the Hitler Youth
Almost all of the discussion about the new pope's Nazi past has centered around his membership in the Hitler Youth as a 14-year-old. But his involvement with that particular group isn't exhaustive of his participation in the Nazi regime.
(The following is from the entry on Ratzinger/Pope Benedict XVI from Wikipedia, which is an excellent resource but which always requires a caveat, since it is a 'collaborative' encyclopedia that anyone can edit. So I am assuming that the following information is by and large accurate, which I am highly confident that it is, considering that many people have been looking at the entry over the past week or so and would likely notice and correct any major errors.)
Two points here worth mentioning. One is that any debate over Ratzinger's activities should not be focused on how much moral responsibility we can attribute to a 14-year-old; Ratzinger was a couple of years older than that and was still serving the Nazi military. A small difference, perhaps, but we are already drawing very fine distinctions in trying to determine the age at which one can be held accountable for his actions.
When Ratzinger turned 14 in 1941, he was enrolled in the Hitler Youth, membership of which was legally required from 1938 until the end of the "Third Reich" in 1945.
In 1943, when he was 16, Ratzinger was drafted with many of his classmates into the FlaK (anti-aircraft artillery corps). They were posted first to Ludwigsfeld, north of Munich, as part of a detachment responsible for guarding a BMW aircraft engine plant from Allied bombers. Next they were sent to Unterföhring, northwest of Munich, and briefly to Innsbruck. From Innsbruck their unit went to Gilching to protect the jet fighter base and to attack Allied bombers as they massed to begin their runs (part of the British terror bombing strategy) towards Munich.
On September 10, 1944, his class was released from the Corps. Returning home, Ratzinger had already received a new draft notice for the Reichsarbeitsdienst. He was posted to the Hungarian border area of Austria which had been annexed by Germany in the Anschluss of 1938. Here he was trained in the "cult of the spade" and upon the surrender of Hungary to Russia was put to work setting up anti-tank defences in preparation for the expected Red Army offensive. On November 20, 1944, his unit was released from service.
Ratzinger again returned home. After three weeks passed, he was drafted into the army at Munich and assigned to the infantry barracks in the center of Traunstein, the city near which his family lived. After basic infantry training, his unit was sent to various posts around the city. They were never sent to the front.
In late April or early May, days or weeks before the German surrender, Ratzinger deserted. Desertion was widespread during the last weeks of the war, even though punishable by death; executions, frequently extrajudicial, continued to the end. In the days preceding imminent German defeat, however, many soldiers deserted. Diminished morale and the greatly diminished risk of prosecution from a preoccupied and disorganized German military, also contributed to widespread desertion. ...
Second, Ratzinger's desertion should not be described as an act of great courage or moral character, which is the way Steve Gilliard seems to see it:
To call the new pope a Nazi demeans the most courageous act in the man's life, running from a Luftwaffe AA battery in a fit of common sense. The Nazis were big on roadside executions and unlike some of the Hitler Youth, he wasn't going to die for Hitler. There were plenty of people willing to ensure that you did. So he deserves ample credit for refusing to fight and to surrender to the Americans instead.
Yes, there was a chance that he could have been caught by German soldiers and executed, but this became less and less likely as the war drew to a close, and it easily could have been the case that Ratzinger made the judgment that he was less likely to be killed by deserting than by staying and fighting. There's no reason to think that this act was 'courageous' or 'a fit of common sense,' unless by that you mean doing what he had to do to save his own ass.
Which, by the way, I am not faulting him for in the least. But let's not pretend that desertion from the Nazi army at the end of the war was indicative of bravery on his part, and let's certainly not pretend that it somehow absolves him of any responsibility for his actions up to that point.