I briefly discussed the German challenge in my previous post, but a conversation during the coffee break was most helpful in clarifying the confusion. So, let me try again.
There is a big difference between Article V operations and expeditionary efforts... maybe. That is, the German cabinet could deploy troops to deal with an attack upon NATO (not just an attack upon Germany) and then consult with Bundestag later. The problem is that the cabinet may dither because they fear what the parliamentarians might do/say later. This is akin to the US problem that the public is not as casualty averse as politicians think, but these perceptions of casualty aversion can cause politicians to pull back (Somalia after Blackhawk down).
This dynamic did appear in Afghanistan in that the Bundestag did not create really tight restrictions for the German troops---the cabinet did, the German defence minister did because of their anticipation about what the Bundestag would and would not accept.
For me, the key concern is that there is still some confusion about Germany's legal constraints--what does Article V mean now as opposed to back in the day? In the Cold War, NATO defense and Germany's defense were one and the same. These days, an attack on Latvia or Turkey may not really endanger Germany.
Which gets to two key dynamics. First, an article V attack is only an article V attack when NATO agrees (consensus!) that such an attack has taken place. An ally could be attacked, such as Turkey, and yet the alliance may not agree that it counts as an attack. Indeed, I use the Turkish case because we have already seen this play out. Second, article V includes opt out language--each country responds as each deems necessary. So, still plenty of room to waffle.
Anyhow, it seems clear to me that any NATO rapid reaction force would not be that rapid, as SACEUR is not being given authority to send troops without consulting the North Atlantic Council and without getting the consent of the countries contributing troops the force. In other words, thus far, no pre-delegation of authority.
And this is not just a German challenge--it is true for many/most/all members. On the bright side, SACEUR can act with his second hat--as US commander of European forces. But that means having some US troops nearby to throw into the mix.
And, yes, I am having heaps of flashbacks to the Cold War. We may not be in the Cold War 2 now, but there are lessons to learn from the past. Russia is not the Soviet Union, but NATO is NATO.