Sorry, but the reality is that most of North India was ruled by foreigners from the 13th century all the way to the 18th century.
I disagree. Turks only had regional Kingdoms in north India just like the natives and like I said before they were struggling, not exactly ruling properly as Imperials would. When one rules a place, they record it as a revenue tract or establish their minister and premanent garrison there. Also their rule in that place should be corroborated by local epigraphic evidence like coins, inscriptions etc.
These don't hold true for "most of North India" with the Turkish hypothesis. Reality is that Turks were mostly confined in town and forts surrounded by numerous native chieftains in the country side. So neither the patchy rule was pan north india, nor its was "all the way to the 18th century."
R C Majumdar : As a matter of fact, the Muslim authority in Northern India, throughout the 13th century, was tantamount to a military occupation of a large number of important centres without any effective occupation, far less a systematic administration of the country at large.
Even till the end of 14th century, we know with surity that the lands of the Delhi Sultanate still were dominated by Rajput and Jat chieftains.
Timur himself testifies to this when he mentions about fighting fellow Muslims only outside the gates of Delhi; but mentions of fighting Jat and Rajput chieftains while passing through Multan, Bhatner, Jammu and Kangra regions.
For Mughals I can agree. They did it differently and thus succeeded. They forged alliances (though that is not the only reason for their success).
If Turks had been so succesfull in north India:
a) We would see much higher muslim population, given the time they had (more than 3 centuries)
b) Babur would not have to fight any serious wars in north India after getting rid of Lodi.
c) The likes of Hammir, Ranmal, Kumbha and Sanga (right next to Delhi-Agra) would not sustain against the Turks for centuries.
d) They would not keep the Turkish Kings & Princes captive on many occasions, that too for months.
e) They would not defeat Sultanates and Khanzadas in battles on all sides (Gwalior, Malwa, Gujarat & Mewat).
f) Sanga would not be breathing down the neck of Lodi, after defeating him twice; having Peela Khal near Agra as his northern boundary. Would like to remind here that Lodis had Agra as their capital !!
g) Kumbha would not raze the Nagor Sultanate down to ground, destroying mosques and forts alike.
h) Mandals of villages would not be harrassing the Turkish garrisons at their bases whenever the latter's main forces were drawn out in battles against organized Rajput forces.
g) We would not see native Kings stamping their own coins, inscriptions, sanctioning construction of temples, ponds etc. Only militarily and financially sovereign, capable States do that.
h) Both sides would not be wresting forts from each other time and again.
i) Kashmir and hill states of Himachal Pradesh wouldn't be out of reach for Turks till 1354 A.D.
Except Iltutmish and Alauddin Khilji (total 45 years), none of the Turks were able to hold sway over majority of north India.
Further, when Khaljis tried to expand into south, they were melted up in north. Jaisalmer, Chittor, and Siwana were lost quickly. Mewar and Marwar went out of reach due to heavy guerrilla warfare. By 1388 even Ajmer and Nagaur were taken back as native Kingdoms and by the beginning of 15th century Jhunjunu near Delhi was regulary raided by the armies of Rana Lakha, emanating from south Rajasthan.
Rana Kshetra Singh defeated Malwa Turks in 1389. 14th century is full of rebellions in Gujarat, Sindh, Deccan and Bengal.
And for when Kumbha came in 15th century, I've already covered the consequences.
Swiftness of Turkish success in Gangetic plains is owing to:
1) Destruction of existing Kingdoms there and lack of clan hierarchies and federation to sustain resistance
2) Conducive geography of the region; native powers devoid of defensive cushion that Mewar and Hilly states had.
3) Lack of quality standing cavalry and forts to match Turkish assaults blow to blow.
Indo-gangetic administrative and military hierarchy forms sort of a sequel of defeats in Dahir (Sindh) and Gakkhars (Punjab) cases.
But elsewhere, from Ala-ud-din Khilji to Aurangzeb in the timeline, mosques were either destroyed or converted into artillery stores all across Rajputana, Malwa and Gujarat. This was a psychological response to temple destruction and demolishes the notion of foreign domination.
It is undeniable that after the initial splendid expansion by Turks, the Khalji and Tughlak territories went back into the hands of the native powers or broke away under rebellious governors. The turks just couldn't build an empire in India in more than three centuries !!
Quite a contrast from there performance in Anatolia; the Ottomans.
Regards,
Virendra
they having nothing to speak of. Extremist retards ruled by suicidal regimes cannot be expected to do any better. India has voted to sanction Iran. That should suffice. 
