In writing about Imperial politics one should first pose the question if such a thing as imperial politics even existed at the time. Everybody would of course agree that there were imperial politics, when 'imperial politics' is understood as the 'emperor's policy'. When on the other hand one wants to say something about the empire's politics the existence of the empire as a political entity must be discussed.
I think that one can say that the empire existed in about the same fashion as the European Union exists today. Just like the European Union it had some revenue sources and unlike the EU, it could declare war or make peace as an entity. There were however notable differences in status between its members: while one member of the Union (the Habsburg state) stood above all others in terms of power and seemed to have a subscription to the imperial crown, some members (Prussia, Bavaria, Saxony) were not as powerful, but still powerful enough to almost completely ignore the emperor. Again other members were almost powerless and depended upon the empire to protect their independence, a fact that gave them the inclination to support its existence. This constellation made that an emperor's policy to advance his power inside the empire would meet with the imperial policy of its members that wanted to keep the balance of power inside the empire. An emperor that wanted to reconquer parts of the empire lost to its enemies would however at the same time reinforce his own power, even if he did not take the lands for himself.
Generals like the margrave of Baden, who was not only an Imperial general, but also himself a sovereign, and the very real existence of imperial armies levied by the Swabian and Franconian Kreis then pose a problem. Should one describe all facts under headings of the different (mini)states, or just throw everything together under an 'imperial' label? Because of this difficulty to make a clear distinction between Imperial policy and Austro-Habsburg policy I have decided to put all members loyal the empire under the heading 'Imperial', while putting rebels (Bavaria) and very independent members (Hannover, Prussia) under separate headings.