So if the collapse of Gaulic power under the Carolingians wasn't enough proof (remember the Vikings hammered Gaul into submission) it seems that the Merovingians even ruled the clergy better than the Carolingians. It wasn't until old Louis the Pious (this is Charlemagne's son) that the clergy began to organize itself and press for political as well as spiritual power; this involved massive land grabs! The Church managed, after much maneuvering and support of several Civil Wars to convince the Carolingians that a King was chosen by god and therefore must be crowned by a Bishop. This of course made them much weaker their their Merovingian predecessors.
The Merovingians were not so easily controlled. Despite the manifold civil wars between the fatheres, sons, cousins, nephews and the like the clergy never exerted authority over them.Quite the opposite the clergy were forever doing the will of the Kings.
There are one of two reasons for this:
1) No dynasty can be really bad ass that begins with a patriarch named Pippen (Charlemagne's grandfater).
2) The Carolingian practice of appointing Bishops from within the clergy wasn't as affective as the Merovingian practice of appointing Bishops from within the Merovingian family!
Post Script: Interestingly the Merovingians did not use the crown in any ceremony either. Seems all the pomp and circumstance of later kingdoms wasn't necessary for Merovich's folks. Of course when your ass is made of iron, what do you care if the seat has a cushion or not!