I read UNSCR 80 [http://unscr.com/en/resolutions/80].
India was an abstention. India never agreed to it.
What India did agree to was the original resolution 47 [http://unscr.com/en/resolutions/47] according to which Pakistani nationals and armymen should withdraw from the state.
In her book Fighting to the End: The Pakistan Army's Way of War, [https://www.amazon.ca/Fighting-End-Pakistan-Armys-Way/dp/0199892709] Christine Fair writes:
"...it is also true that Pakistan never fulfilled the first requirement, to demilitarize, on which the rest of the process hinged (Ganguly 2001; Nawaz 2008a, 2008b; Whitehead 2007). Oddly, while many Pakistanis continue to insist that the plebiscite be held, Pakistan was not enthusiastic about the idea when India first suggested it in 1948(Wirsing 1998). Equally important, most contemporary Pakistani commentators have forgotten (or simply choose to ignore) that Pakistan-not India-failed to fulfill the first, necessary, (if insufficient) condition for the now much desired plebiscite, making Pakistan unable to blame India alone for its failure to meet subsequent obligations. It should be noted that in my varied interactions with Pakistanis in and out of uniform, I have never met a single individual who can recount what UNSCR 47 actually demanded of both states even though many Pakistanis continue to insist on its implementation."
It may be noted that even if India were to agree to a plebiscite as per UN resolutions, it has to be held in the whole of the state, which includes the part under Pakistani control and the part ceded to China. [https://en.wikipedia.org/wiki/Sino-Pakistan_Agreement]
The Sino-Pakistan Agreement (also known as the Sino-Pakistan Frontier Agreement and Sino-Pak Boundary Agreement) is a 1963 document between the governments of Pakistan and China establishing the border between those countries. It resulted in China ceding over 1,942 to 5,180 square kilometres (750 to 2,000 sq mi) to Pakistan[citation needed] and Pakistan recognizing Chinese sovereignty over hundreds of square kilometers of land in Northern Kashmir and Ladakh.
I realize that there's some controversy regarding this. Pakistanis claim that they never controlled those lands. Whether or not they controlled it, it formed part of the land under consideration by UN. Chinese have told India that it was an agreement between two sovereign nations and to forget about it.
Why did Pakistan cede a huge part of the land it regards as unfinished agenda of Partition?
Why has Pakistan annexed the area of Kashmir under its occupation? Why did it assume that this is what the population wants? Why did it not hold a referendum ?
If the plebiscite were to be agreed:
(a) would they get the land back from China?
(b) unpopulate area occupied by them of their own nationals and allow only Kashmiris to participate?
In 1954, Pakistan and US signed a mutual defence assistance agreement. Nehru withdrew the plebiscite offer to Pakistan. [https://en.wikipedia.org/wiki/Timeline_of_the_Kashmir_conflict#1950]
Why didn't Pakistan agree to the terms of the UN council resolutions from 1950 to 1954?
Why does Pak offer "moral" support to those who conduct terrorist acts in India? [https://www.aljazeera.com/indepth/spotlight/kashmirtheforgottenconflict/2011/06/2011615113058224115.html]
Her recent book Fighting to the end - Pakistan Army's way of war explores this in greater detail.
She started out as more neutral on Indo-Pak affairs but after spending 15 yrs in Pakistan, reading Pakistan army journals and other statements made by Pakistanis, has moved over to the Indian side. Her argument is that even if Kashmir was to be given completely to Pakistan, it would not stop waging war with India coz Indo-Pak tensions are not abt Kashmir or security but abt ideology.
She is soo hated by the Pakistani establishment, that the ISI threatened to gangrape her and she is banned from visiting Pakistan.As a protege of Stephen Cohen (who harbours similar sentiments), i hope her arguments would have more resonance in the American establishment.
For a summary of her arguments, watch this.