My gf's family comes from one of the alleged 'capitals', though more like meeting arena than political nerve center, so I've been interested in this for a while.
Find E. T. Salmons work Samnium and the Samnites
It has a lot of brilliant work on the Samnite wars. The major difficulty of early Roman history is that is was mainly collected by families trying to fluff up their own achievements (wether they had to make them up or not). He does a fantastic job of picking apart the First and Second Samnite Wars as they are full of made up battles and he complains about Consuls and Legates who end up in two places at the same time according to Roman historical record.
Rather hilariously Salmon picks out the large amount of battles in the First and Second Samnite Wars the Romans describe as "lasting until nightfall" that the writers refuse to admit the Romans lost or went undecided.
Livy is apparently the worst when it came to the record avoiding a large period of the Second Samnite War to go into his own bizzare alternate history of how the Romans would have beaten Alexander the Great had he invaded Italy (which is utterly laughable). He also uses it to avoid talking about periods of Samnite successes against Rome. Current translations (or perhaps just the one I have) shunt this tangent to the appendix to avoid messing with the flow of the history.
Samnites were more federal in outlook than the centralised Romans. The Samnite League consisted of 4 major tribes; the Pentri (the largest); the Hirpini; the Caudini (of the Forks fame) and the Caraceni ('Those who dwell among the rocks'). The Samnites were herders mostly and lived in austere and rustic conditions. They built their towns on hilltops and guarded all the entrances to their high home with strong fortifications. It was only during Roman domination that they were forced off the hills.
When their population would become too large they gathered all those willing to leave, or those who had been "sacrificed" as children to Mamers for a victory in battle (known as the Sacrati) and began a migration from the mountains to better pastures under the banner of a totemic animal like the wolf (hirpini and lucani) or the bull like the Samnites themselves. So they could spread their domain through Sacrati settlements like the Roman coloniae.
It was this wanderlust that caused friction and then outright war with other Italian peoples.
To gain victory in desperate battles the Samnites would make a deal with the god Mamers to sacrifice their first born of spring both animals and children. The first born of all animals as part of the deal were actually sacrificed, the children however were called the Sacrati and were destined to lead migrations into new lands under a totemic animal.
Samnium (or Safinum in Oscan) was divided up into districts. Each town and the land around it was organised by a figure called a pagus, several pagus would take orders from a Meddix and several Meddix would take orders from the Meddix Tuticus, rather similar to Roman Consul, but there was only one. The Samnites had powers given to their leaders similar to the Roman Imperator though it was Embratur in Oscan.
The Samnites had a special religious military organisation the Legio Linteata or Linen Legion. Sworn by strong oaths they numbered in the tens of thousands and were devoted to serve the League.
An Italy dominated by the Samnites would likely be under a federation dominated by the Samnites. They likely would not have expanded beyond Italy and would have clashed mainly with the Hellenic adventurers serving Tarentum or other cities in the Magna Graecia. Samnite mercenaries would likely be as common as Gallic mercenaries throughout the Mediterranean serving in others wars and taking over cities and establishing tiny Samnite or Sabine enclaves like the famous Mamertines of Sicily.
Lol, yeah. There's an undoubted respect for Samnite military prowess and toughness that filters through, but all the usual Roman rationalizatioms. Maybe the most interesting aspect is how much like modern imperial apologists their routine sounds, and is true here, where according to Rome the pattern pretty much always goes:
1) Rome sitting there minding it's own business, nary a thought for the world beyond their borders.
2) Barbarian State A attacks somewhat less Barbarian state B for no good reason, just pure unadulterated greed for the material wealth/land/control of B.*
3) B comes hat in hand to Rome, begs for assistance against those A bastards...and generally offers up all their material wealth/land/control in return. Presumably everyone and their neighbour would much prefer losing everything to Rome rather than losing everything to anyone else because reasons.
4) Rome debates. Much hand wringing and reluctance to acquire all that wealth/land/control, but usually persuaded round by the thought of martial duty and glory. By usually I mean always.
5) Rome declares war on A. Wars happen. Now, like with say the Brits and Napoleon, you need to understand that from this point onwards all the wars and broken peaces are A's fault, irrespective of how many times it's Rome 'technically' declaring war/breaking peace treaties. If anything is ever so obviously Rome's fault that it can't be completely ignored it still won't be Rome's fault, but rather the fault of a specific individual Roman who was always too much like A for Roman tastes anyways, and every good Roman says so.
6) Often at some point along the way...possibly when 'confusion' arises over just what, where and when they agreed to give up everything to Rome in exchange for protecting...er...the nothing left over, you might see B 'betray' Rome and pitch in with A, those traitorous bastards. At this point it becomes a war of Roman honour and revenge, and you can almost hear the protests against acquiring all the wealth/land/control wailing out from the Forum. Still, they'll manage somehow.
7) In the end Roman endurance, toughness, intelligence and sheer rightness-ness wins out and you have Ovations and the odd triumph. You'll also have some generals who lost a battle anti-climatically unexpectedly forgiven...demonstrating Rome's pragmatism and enlightenment and then you'll have soldiers who lost unexpectedly banished/killed/punished, demonstrating Rome's martial vigour, honour and determination. Marx might identify slightly different rubrics at play, but then he's from north of the Olive Line, so what could he possibly know about anything?
Anyways, the gist is that contrary to what many think, ancient Imperial powers with any kind of representative structure were often just as prone to constructing apologetic narratives that excuses their acquisitiveness, and most if not all Roman invasions would be under the banner of quasi 'intervention'...if not at the time, in very short order after the fact. Nobody is the bad guy in their own movie, and that commonality with modern expansionist 'interventionist' powers is imo very entertaining, if a bit sad.
*there is a variant where Rome itself is attacked directly, but that's pretty rare.