From: Eagle River, Alaska
Agree with Golden Bear. My testing shows that the ground war pretty much happens according to the historical schedule no matter if you bomb the heck out of them or ignore them entirely. So the only time I would bomb them is when forced to by political requirements, although as Golden Bear points out, there are more worthwhile targets to hit when you are forced to which will help your overall campaign. His point about making use of them to bring up morale is an interesting one which frankly never entered my mind. Neat idea.
One thing to note, when you do get forced to use bomb the political targets, consider using the maximum force possible to inflict enough damage to satisfy the requirements as quickly as possible - so you can get back to bombing what *you* want to. When the 8th AF gets restricted by Overlord requirements, the AI uses a minimal amount of heavy bombers, if it participates at all. This only makes the Overload requirements stay in effect longer because only the tactical airforces are hitting them. In tests, often the only way the AI gets out of Overlord requirements is when the ground forces advance and occupy France, which means the Combined Bomber Offensive is basically on hold for months, letting the Germans recover. You don't want to follow that example.