It was to Kosovo that Germany sent troops for the first time after WW II following long and hard discussions in the german parliament. Stupendously it was a left wing government (green pacifsts and social democrats) that had to take this decision at the time. Since then they participated in the war against terror mainly in Africa and Afghanistan but were harshly against the recent Iraq war. Two years ago they sent their navy during the israeli invasion of lebanon to control the embargo.
But even they went to war german troops always had a kind of special role either surveilling or securing boarders or doing build up missions in remote areas.
During the munich security meeting this year NATO members "kindly" urged the germans to send combat troops to the south of Afghanistan to support canadian and english troops which Germany denied offering to extend the securing mission in the north and sending more transport helicopters. The central argument to deny has always been the german "past" with horrible crimes commited by the german armed forces during WW I and II.
In my opinion we (i am german) can t go on like this. We have been protected over decades by NATO forces! How long can we "hide" behind WW II and the holocaust? If we defend our "own" security in Afghanistan (like our former defence secretary said) Germany will have to accept sending combat troops, i think. This implicates loosing soldiers in combat! This might sound ridiculous to non-germans but principally that s what the fuss is about. We think we can go to war but just a bit..."avoiding" human losses. I m sure the german government is aware of that. The question is which politician will take the first step and then loose the next elections because of dead german soldiers coming home....:-/