Just want to interject here with some historical facts people seem to be forgetting.
1. It is not called an "Indian civilization" it is called the "Indus civilization" there is a difference
How does that make a difference as Indian itself is generated from Indus??. If fighting over name then there are No mention of Pakistan in any textbooks 60-70 years ago so lets not discuss about that. Whole world knows 1947 as partition of British India as India and Pak except ofcourse people like you.
One more clarification for You, Pakistan was a land given for Muslims who want to separate state for Muslims, few migrated, few didn't, few made East Pakistan which later changed to Bangladesh. Now before 1971, If India does not have right on Indus valley civilzation then how half of Pakistan (Now B'desh) claims Gandhara/ Indus valley civilization?? Migration of people and current land does not authorize cultural heritage for respective era as land changes people come and go.
2. India was NEVER a nation until 1947, it was always warring states who occasionally were conquered and integrated into an empire.
Right, India was not there but Indus was there Indus civilization was there.There were group of kingdoms were there which were called as India and that is why in 1400 AD Columbus was in search of India and not Kamboj/Gandhar. This is also evident why Red Indians/Indiana states were on name of Indians because of mistakes made by explorer. Oops no Pakistan here again same India!!
History problem or denial we u'stand both. It is just reflex of Inferiority complex.
3. The Original vedic religion of the area called Pakistan was Buddhism but the Hindus forcibly converted the Buddhist to Hindus by the time the Muslims had gotten there. That's why there are not many Buddhist left in Pakistan, or India for that matter.
Again trying to be History professor?? Hindus forcibly converted Buddists to become Hindus.. Great!!.. Just check then if your forefathers were forced to convert by Mughals/Mongols.. Equation completed..
Anyways, just to enlighten you (God knows why i am trying!!) First of all there were no religions as Hindu that time.. it was a blanket geographical name so if you are so obsessed with Indus then you are also Hindu as Allama iqbal says "Saare jahan se Accha Hindositan hamara".. He was not praising a religious Hindu land and then making a Muslim land named as Pakistan.
So fight was between Vedic (Sanatan) and non-vedic religion (Buddhist or Jain) but then assimilation of Buddhists and Sanatan dharmi took place when Buddha was considered as 9th Avatar for Lord Vishnu.
PS: For all sane people who want to accept cultural heritage then learn it from Iran, those who are Muslims today but respect there Aryan roots and Persian culture.