Well first india is not an ethnicity so someone expanding into some other part is extending its reach into the area of other ethnic domain. Specially the difference between north and south and east and west indians is very much clear. Even if this doesn't convince you then maurya had extended its kingdom into half of present day Afghanistan and present day balochistan and they under no definition fall under indian ethnicity. Moreover he also battled Seleucid empire and tried to increase his influence further in west and north
Let me put it to you that India was not an ethnicity, but a series of interconnected ethnicities, some dividing along language, many more across apparent race (genetically, all Indians, and some Indians who are today no longer very comfortable with the term 'Indians', fall into either Ancestral North Indian or Ancestral South Indian).
The differences between north and south and east and west Indians that you see goes one step deeper at least, and perhaps more; they remain bound together in the general inter-relationship. So if you stop for a moment and throw the cardinal directions of the compass into the nearest waste-paper basket, you will find that 'India' sub-divides into river-based civilisations, BUT NOT the ones about which we argue on PDF morning, day and night. Instead, consider looking at India as based on the Ganga-Yamuna river complex, the Brahmaputra, the Meghna-Padma, the Mahanadi, the Godavari, the Krishna, the Kaveri, the Tungabhadra, the Narmada and the Indus. Only a narrow strip of land in Kerala falls outside these matrices.
If you continue to examine these river-based civilisations, you will find, perhaps to your surprise, perhaps not, that each has strong borrowings from the ones closest to it on all sides; so, for instance, the Ganga-Yamuna complex borrows from the Indus complex in Punjab and Haryana, or the other way around, if you please; the Meghna-Padma borrows from its upstream neighbours the Ganga-Yamuna culture, and on the other side, the Brahmaputra based culture; and so on, and so forth. If you have the patience to dig a little, you will find an enormous amount of debit and credit transactions taking place on the cultural balance.
Effectively, nobody is expanding into anything that he or she is not already partly related to. When the Rastrakutas kept all of north India under their iron grip, they finally landed up contributing a famous Rajput tribe that reigns over much of Rajasthan. So how do we define the Rastrakuta? As children of the Narmada, or the Tungabhadra, or the Ganga-Yamuna cultures?
Then you have been very, very brave, kept the terrible mischief being wrought by Ajit Doval and his wicked band of imps, and forestalled any historical adventurism by saying that half of present-day Afghanistan and present-day Balochistan (spoiler alert) under no definition fall under Indian ethnicity. If we define Indian ethnicity as people speaking Punjabi or Gujarati, certainly; you have a point. The population of left-handed red-headed green-eyed dwarves of three feet of height and below is certainly a most well-defined one. When the Achaemenids ruled those areas, Arachosia and Gedrosia were certainly not kept isolated from other parts of their empire, not even from frontier marches like the hill country that was many centuries before known as Gandhara, and would use the name again very soon. These tracts had come into disrepute, as the abode of the mlechhas (you may have come across this term during its use in later years to sneer at various breeds of 'outsider' to India, but this was where it was first used), who no longer spoke the pure tongue; they did not speak what was become the standard for speech in the 4th and 5th centuries BC, the language as spoken in what is today western UP. Even the immediate neighbours in the Punjab and in the valleys and ravines of the north-west were viewed with a certain degree of condescension. So the Kamboja became outliers, where they had been in the heart of the matter earlier; so, too, were other tribes like the Uttara Kuru and branches of the Madra. Most of the north-west, and most of the south-west was populated by tribes who had grown over the centuries closer and closer to the mainstream Medes, then the Persian conquerors, but that by no means consigns them to a different ethnicity altogether; there was as much resemblance between them and the people of the Indus Valley as there was between the people of the Indus Valley and the people of the Narmada.
This is strictly with reference to the Mauryas. Once they had given way to the waves of barbarian assault that followed, the Scythians gave their name to the Seistan Desert and also ruled in Gujarat and Malwa as Satraps under different Emperors; there was no lack of ethnic commonalty at that stage.
If you have the patience to follow up these broad brush strokes, you might find a very different picture emerging. You will have to do it alone, because I will not respond to requests for texts and citations; this post itself has been taxing, and I will need to recuperate from it.
Mauryas succeeded the nandas, whom i believe had already a vast empire stretching from ganga to tamil nadu, given the geopolitical situation kautilya strived for a more ''dharmic'' rule under the mauryas. I dont think it had indian nationalism in mind but the geopolitical situation.
The indian kingdoms have got united under thread of what they called ''mlecchas'' so its not like the mauryas had no indian nation in ther mind while trying to stretch to all the corners of what they called ''jambudvipa'', the mauryas and kautilya believed three corners of india, whether it was politically united under one state or several, the entity remained there regardless.
regards
I just mentioned the 'mlechhas'
a couple of posts down, above, hoping very hard that I would not be hooted out of the forum. You really have a breadth of learning.
Am I forgiven or are you still cross?