The idea that the Merovingian state was the private property of its kings, explaining thus the divisions of the regnum among their sons, is largely obsolete : as it was the case for most of Barbarian kingdoms that replaced the Roman Empire in its former western provinces, it mostly inherited its institutional conceptions and a clear difference was made between the fiscus, the public property of the king (and, formerly, the emperor) and the regnum as the space on which the public authority was exerted.

It doesn't mean, however, that these institutions remains intact or even that they wholly survived : the late imperial public service largely depended from the imperial fiscal capacities for its waged subsistence. Yet, this is precisely what broke down first with the collapse of imperial authority, which was particularly felt in Northern Gaul since the 460's. While the Late Imperial militia (the administrative and military public service, which tended to be merged by the Vth century, along with the tolerance and legalization of practices formerly associated with nepotism, profit-sharing and corruption) survived relatively well in Spain, southern Gaul and Italy (especially with its revival under Theodoric), it appears to have been particularly diminished north of the Loire, probably due to the political disorders (although it didn't outright collapsed together with other social institutions as in Britain), and the major figures we know about are mainly religious (St. Genovefa; St. Remi, etc.), military (Aegidius, Paulus, Riothamus, Syagrius) or both (possibly the case of Arbogast of Trier as count and bishop of the city) even if the contact was never cut down with other provincial or late imperial elites.

Basically, even before Clovis conquered northern Gaul, the reality of a public service seems to have been more of an idea than a reality. Bishops, that weren't part of the former public service, became a recruitment poll of advisers and administrators for the early Merovingians (which eventually led to the idea receiving the mitre was crowning sort of a secular public career), along with an ill-defined figure named grafio until the mid VIth century (essentially a public servant missioned and waged by the royal power but probably outside the recognized de facto jurisdiction of cities, i.e local nobility and bishops) and the centenarius (formerly a military officer, and in the VIth century, sort of agent of public order under the grafio). Ultimately, Clovis' rule (and his sons') was closer being a warlord's on a less sophisticated Roman society than the transmitted public power that existed in Spain, Viennensis, and even less Italy. What was important was the proximity with the royal power and the aristocratic display and apparatus; rather than holding on old references (something interestingly closer to how Barbarians acted before being settled as autonomous imperial polities in the early Vth : in some ways, Franks were lagging behind)

Still, as diminished it was, the idea of public service remained as a model and along the Frankish conquest of southern Gaul and its more "Roman" apparatus. And a new public service emerged out of it in the VIth century : maintaining a realm at sword-point required regular victories, a method that reached its limits against Goths in Spain and Byzantines in Italy. Having "cleaned" or tributarized its political orbit (altough Merovingian claims of being overlords of Armoricans and Anglo-Saxons, if not entirely devoid of truth, shouldn't be taken at face value), consolidation became a priority. The Theodosian Code as a reference, a "new model administration" was created, new realities under old names (although this was hardly a Frankish, or even a Barbarian, phenomenon) especially as the proximity with the royal power (from the king, but possibly from the queen as well) remained normative. This public service seems, comparatively to what existed in Spain, Italy or the Eastern Roman Empire, relatively less sophisticated and ill-defined (if more present than it was even in the Late Empire, in everyday life), or at the contrary specifically tailored to the needs : counts had a fiscal role as well as military, judices could intervene in a variety of issues, dukes were ad hoc functions depending of the current problems, etc.

Overall, Merovingians were seemingly big believers in institutional laisser-faire, power delegation (rather than commissioned power) and ad hoc interventionism, local management (judex locorum) being mentioned only when the royal power had to intervene, and even there rather delegating its power than imposing their immediate interests or politics as a principle. As it happened for justice, they rather elected to preserve social peace than supporting a principle for the sake of it, which meant corruption (either hidden or openly made trough "gifts") and promoting competition between kings (which explains the attachment of Frankish aristocracy for the preservation of several palatial networks). This public service wasn't really waged, but not yet landed and was rather payed trough the attribution of fiscus' production or benefits, or the attribution of privileges; notably the legal (or para-legal) enrichement on fiscal or fine perception : as long as te royal power was able to not only control these delegations and to provide for a limited time both privileges and fiscal attribution to their agents (partly trough outright confiscation of lands and goods to increase the fiscus when raiding couldn't do), it was fine enough.

A general pragmatism seems to have dominated at the apogee of Merovingian Francia : the royal power intervened when its interests or social order was threatened, or when giving free rein was deemed too harmful (as in the management of fiscal revenues in Provence, which represented too much for being let to the rapacity of local families). In that, these kings were helped by a political power and prestige that remained largely intact when it was significantly diminished in Gothic Spain (where it devolved into an anti-dynastic kingship) or Lombard Italy. More often than not, the kings acknowledged the situation on the ground and nominated an important representantive of local families; rather than appointing governors or judices according his own priorities and perspectives.

Still, the division of the regnum didn't just obeyed to dynastic logic (preventing usurpation, undue war of successions, allowing to act on several fronts: more or less as it worked down with the imperial collegiality in the Late Empire) but also the request of regional aristocracies, either from public service, either from "royal", militarized and landed elite. As the access to the royal palace was determining into making a noble and/or a career; a regional king (either a son, a nephew or a generational member of the Merovingian dynasty), having a distinct king was often deemed necessary to preserve one's family power against the ambition or the rivalry of others (to the point, besides the three usual sub-kingdoms, you even had ad hoc creations such as the kingdom of Caribert II in Aquitaine, although it did fit political-military necessities against Gascons too; or the whole mess that was the tentative of a kingdom of Aquitaine by Gondovald and his supporters).

Bruno Dumézil proposes to see the territorial management of the Merovingian realm as an onion : the healthiest center, the Frankish sub-kingdoms proper being largely a Roman-like state, as in Aquitaine or Provence (although less directly controlled by the royal palaces) but the periphery being controlled not trough public service but personal relationship and "blood" nobility (Gascony, German duchies) and (southern England being *maybe* in-between these peripheries) eventually outright warlordism in Frisia, Saxony, Italy, etc.