Why was the Holy Roman Empire weak in comparison to the Church?

Answer 1

The Holy Roman Empire was a strong political entity in the Carolingian era, much stronger than the Church as an organization. From the Middle Ages on its centralized structure fell apart and it became a loose confederation of States on the territory of present-day Germany and Austria. The Emperor from then on might have a lot of prestige because of his title, but his effective power was mostly confined to the State where he himself came from. The other local rulers who acted as Electors moreover had every reason not to elect someone from their midst as Emperor who might start throwing his weight around. In theory, the Emperor could call up his 'subject' rulers and their armies to war or decide on a joint policy. In practice, it took a lot of cajoling to get them to cooperate on anything.

The Roman Catholic Church did on the contrary not start out as a strong and centralized organization. For the about first 1,000 years of its existence the Pope could only rely on his moral authority (if he happened to have it) and many rulers saw local Bishops simply as part of their own feudal structure - and many bishops also happily acted the part. Only gradually a Church hierarchy came about in which the Pope became the effective and sole ruler of the Church as an organization.

So, in the early Middle Ages the Holy Roman Empire was - contrary to what your question suggests - much stronger than the Church organization. Only much later on, the Empire's central structure fell apart while the Pope managed to finally establish himself as the Head of a centralized organization.