So this is an excerpt from an essay I wrote on the topic that essentially summarizes the conflict. I have cited the sources used in this section at the bottom, hope it helps. If this is not allowed, I will remove it ASAP!

As both India and Pakistan gained dominion status in mid 1947 around 600 princely states had to be politically integrated into the newly formed dominions. Before 1947, the princely states had operated in conjunction with the British Raj, forming a type of relationship that came to be known as paramountcy. Princely states would cede certain powers, such as control over foreign affairs, to the British. With the creation of India and Pakistan in 1947, as per the June 3rd plan, the relationship of paramountcy between princely states and the British ceased to exist; states regained control of the powers they had initially forfeited to the British Raj. In order to fill the vacuum left by the British, states were supposed to form allegiances (generally based on state demographics and state geography) with either Pakistan or India, as per Lord Mountbatten’s June 3rd plan. Allegiances were formed, for the most part, using instruments of accession, through which princely states would either accede to Pakistan or India.

For the most part, the majority of the princely states acceded without too much fuss. However, there were 3 notable exceptions to that rule: Hyderabad, Junagadh, and Kashmir. In this essay I will be looking at the cases of Junagadh and Kashmir.

As the Junagadh conflicted played out in Gujarat, another crisis was unfolding in the princely state of Kashmir. Unlike Junagadh, where the leader was a Muslim and the majority of the population was Hindu, Kashmir had a Hindu leader and a Muslim majority. However, even though the majority of the population was Muslim, this did not mean the whole Muslim population was in favor of acceding to Pakistan; one of the state’s most popular political party’s was the Sheikh Abdullah led National Conference, which shared extremely close ties with India’s congress parties. When India and Pakistan became separate dominions, Kashmir, unlike Junagadh, did not announce its intentions immediately. Rather, Kashmir entered into a standstill agreement with Pakistan, and also attempted to enter into a similar agreement with India (albeit unsuccessfully). As time progressed the situation in the state became less favorable towards Pakistan. Mahajan, Kashmir’s Prime Minister was in talks with Nehru over accession to India. As a result of these talks Sheikh Abdullah, whose popular following and ties to India made him a threat to Pakistan, was released from jail. With the situation slipping through Jinnah’s fingers, he decided to resort to military action. In a telegram to Jinnah, Major Khurshid Anwar discussed the plans to send Pakistani tribesmen into Kashmir. In a telegram on October 18th from Kashmir to Pakistan it was noted that transport of supplies and efficiency of postal services was becoming increasingly difficult owing to the presence of tribes men. Then, on October 22nd tribesmen seized Muzaffarabad. With pressure mounting, and the situation becoming increasingly desperate, Kashmir’s ruler, Hari Singh, acceded to India in the search for military help in restoring peace within Kashmir. In a note to Lord Mountbatten, Hari Singh says, “I have no option but to ask for help from the Indian Dominion. Naturally they cannot send the help asked for by me without my state acceding to the dominion of India. I have accordingly decided to do so”. The Indian government decided to accept his accession until peace was restored. After that, they would gauge the will of the Kashmiri people, and make a decision from there. Hari Singh’s accession, was hotly contested from the getgo. Pakistan maintained that he was no longer in control of his state, seeing as areas of northern Kashmir had been clinched by Jinnah’s tribesmen (In denying the legality of Kashmir’s accession, Jinnah simultaneously denied India’s right to Kashmir, but maintained his own right to Junagadh, because nothing illegal or questionable had happened in Junagadh). But regardless of Pakistan’s objections, India now labeled them aggressors; their “troops” were on foreign turf. Over the following 2 months, rhetoric between the two sides escalated. Various proposals, some of which will be further discussed later, were put forward, but then ultimately rejected. Amongst these proposals was the swapping of Junagadh for Kashmir and an immediate plebiscite to ascertain the Kashmiri populations will. The idea of a plebiscite gained headway, but ultimately reached an impasse when neither side could agree on conditions; both sides wanted a plebiscite to be carried out in conditions that would be favorable to them. Both India and Pakistan eventually took the case to the Security Council. Resolutions were offered in both April and August of 1948. In April, both India and Pakistan rejected the Security Council’s proposal. The proposal required both countries to withdraw their troops, and then a plebiscite administration would be set up. The administration would invite all major political parties of Kashmir to participate in the plebiscite. India rejected the offer saying it did nothing to acknowledge Pakistan’s role as aggressor, and it pitted the two countries as equals, which, in this situation, India claimed was not the case. Pakistan rejected the proposal because the inclusion of major Kashmiri political parties would mean Sheikh Abdullah and the National Conference would play too big a role in determining the outcome of the state. In August, only Pakistan rejected the UNs new resolution, which implicitly confirmed Pakistan’s aggressor status. India, given the changes, found the new conditions favorable.

Why was Kashmir important (india centric answer)?

Kashmir was of key importance to India because it supplied (and still supplies) many of India’s rivers with water, which in turn sustained multiple communities across Northern India. At the same time being in control of Kashmir’s water supply would also mean India could control water flow into Pakistan. Serving as the basing for the Indus river, securing Kashmir would mean securing and controlling the water flows to various rivers across North India. In fact, during military operations in 1947 and 1948 Jhelum became a key point of contention. General Gracey became increasingly aware of attacks on Bhimbur and Mirpur, noting that such an attack would allow India to control the Jhelum, one of the key tributaries of the Indus.
Furthermore, successfully gaining Kashmir would, Nehru claimed, prove India’s status as a secular state. According to Nehru, “If Kashmir went, the position of Muslims in India would become more difficult. In fact, there would be a tendency of people to accept a purely communal Hindu viewpoint. That would mean an upheaval of the greatest magnitude in India”. Having a state with a majority population of Muslims in India would declare India as a secular nation. How could Kashmir exist within the framework of India if it were not a secular nation? Wresting Kashmir from Pakistan, an Islamic nation state, would be the ultimate victory for India’s secularity. Finally, with Indian control of Kashmir, would make sure that India’s internal security was safe. Northern Kashmir bordered Afghanistan, China, and the USSR at the time of independence. Having a secure Kashmir would secure India’s borders and possibly prevent future incursions by the aforementioned countries. In a telegram to Clement Attlee, Nehru had the following to say as to how a secure Kashmir would reinforce India’s own security: “Kashmir’s northern frontiers…run in common with those of Kashmir, which must depend upon its internal tranquility and existence of stable government, is vital to security of India, especially since part of southern boundary of Kashmir and India are common”. Securing Kashmir would expand India’s presence in the subcontinent and the surrounding area, which would serve to deter potential incursions. Furthermore, Kashmir’s difficult to navigate terrain would also serve as a deterrent for those trying to enter India, especially if the Indian army were able to master the mountains and valleys that enveloped Kashmir.

The section I copy pasted is mostly context and derived from the following sources. Hope this helps!:

Menon, V. P. The Story of the Integration of the Indian States, 130. New York: Macmillan, 1956. Print.

Zaidi, Z. H., and M. Akram. Shaheedi. Quaid-i-Azam Mohammad Ali Jinnah Papers. Islamabad: Quaid-i-Azam Papers Project, National Archives of Pakistan, 1993. Print. 5

Raghavan, Srinath. War and Peace in Modern India. Houndmills, Basingstoke, Hampshire: Palgrave Macmillan, 2010. Print.

Lamb, Alastair. Kashmir: A Disputed Legacy. N.p.: Roxford, 1998. Print.

Hasan, K. Sarwar. The Kashmir Question. Karachi: Pakistan Institute of International Affairs, 1966. Print.

So, I wrote my masters thesis on the evolution of Indo-Pakistani relations, in the context of Kashmir. This will be a pretty long answer, but below I have pasted some of the most relevant pieces of my thesis. I haven't touched it since 2012, so there is nothing in there post-12. If anyone is interested, I will gladly share the entire thing.

Ya, so this is pretty long, and goes into the 1st child comment. The format sucks but I don't feel like spending an hour getting it to look good for a Reddit comment.

The beginning of the conflict:

Prior the partition of India, the Indian subcontinent consisted of British administered provinces and more than 560 princely states.28 These princely states, though they recognized the supremacy of the English Crown, were largely internally autonomous. Upon the partition of India, these princely states were given the choice to accede to either India or Pakistan. The overwhelming majority of these states chose to join the new nation that corresponded to their internal religious demographics; however, some were swayed by other means. Most of these princely states were demographically Hindu, so the great majority acceded to India. However, as India was quickly expanding its territory with the incorporation of these states, Pakistan made securing the few majority Muslim states, specifically Kashmir, its key policy goal in its early existence.

Kashmir or, at the inception of the new nations of Pakistan and India, the princely state of Jammu and Kashmir, was asked to join one of the new nations. However, the Maharaja, or king, of the princely state, Hari Singh, was very reluctant to make a decision.29 There were several reasons for Singh’s reluctance. First, Singh was a Hindu and his state was largely Muslim. While logic would suggest that Singh favored accession to Hindu India, this was not the case; Singh’s ultimate goal was for Jammu and Kashmir to emerge as an independent nation, or at the very least a part of either India or Pakistan with a large degree of autonomy.30 Further, the Maharaja was very skeptical of Indian socialist intentions of Jawaharlal Nehru, the Prime Minister of India; he was also skeptical of the possibility of Pakistan greatly diminishing his power.31

When the question of accession was initially posed, the people of the Poonch region of Jammu and Kashmir became very visibly active in their favor of joining Pakistan, holding public forums and debates, as well as lobbying the Maharaja. Though the Poonchis activism began peacefully, the Maharaja responded with a strong hand. Singh ordered a large contingent of his Hindu troops into Poonch to halt the activism.32 The largely peaceful protests soon escalated to violence as the Maharaja’s troops, in early August 1947, fired upon a peaceful protest.33 This gave rise to a widespread armed conflict, between the Hindu troops and the Poonchis. On 27 August 1947, Poonchi rebels attacked and took control of a police station.34 This caused Singh to send in nearly all the troops under his command into the Poonch region, escalating the conflict into all out civil war.

Though the conflict itself began in Poonch, it soon expanded beyond, with many Kashmiri Muslims taking up arms against the Maharaja’s troops. In the midst of this civil war, Pakistan saw an opportunity to achieve its goal of incorporating Kashmir. It seemed, to the Pakistani leadership, that a small push was all that Singh needed to accept the accession to Pakistan.35 Therefore Pakistan began to arm the rebels. Further, Pakistan set into motion a plan, several months in the making, to invade the region. The plan materialized on 22 October 1947, when more than 2,000 irregular Pakistani troops—consisting of former soldiers, tribal militias, and a dozen or so plain-clothed Pakistani officers—crossed the border into Kashmir, and joined with the already active anti-Maharaja Kashmiri militias.36 These irregulars, after several days, began to close in on the capital of the state, Srinagar.

With the Pakistani-Kashmiri militia closing in on the capital, India dispatched a delegation to persuade the Maharaja to join India. On 26 October 1947, the Maharaja signed a letter of accession to India, on the basis of India’s promise that it would send troops to halt the rebellion.37 This letter still remains at the core of the Kashmir conflict. Pakistan holds that the letter was illegal, and “India’s continued refusal hold a plebiscite on the question of accession denies the Kashmiri people their right to self-determination.”38 Further, Pakistan argues, the letter was illegal as the Maharaja of Kashmir was not a heredity ruler, but rather was appointed the British colonists.

Legality aside, once the Maharaja agreed to accede to India, Indian troops were airlifted to Kashmir.39 Once arriving at the end of October 1947, the Indian forces quickly secured the capital. By the end of November 1947, the Indian army had taken over the war effort, which at this point was strictly defensive in nature, from the Maharaja’s troops.40 With the introduction of the Indian regular army, the Pakistani-Kashmiri effort faltered. This was due to an array of circumstances. First, the Pakistani-Kashmiri militia was highly disorganized and unprofessional. Often the actions of the various Pakistani and Kashmiri tribes, which made up a large part of the Pakistani-Kashmiri militia, were dictated by tribal elders who, more often than not, were focused on pillaging and looting villages. Officers were unable, to a large degree, to coordinate their actions against the Indian army.41 The difficulties in coordination of the Pakistani-Kashmiri militia were compounded by the fact that the Indian army, as a result of the division of assets, was highly professionalized and utilized the most modern military equipment.42 The Pakistani- Kashmiri militia was, on the other hand, “a rag-tag force equipped with outdated rifles or homemade weapons in the gun factories of the Frontier province.”43

As the winter months of 1947-48 came on, the war ground to a halt. This lull gave both sides a chance to reevaluate their strategies and goals of the conflict. Jawaharlal Nehru, at the coaxing of his British advisors referred the issue of Kashmir to the UN. However, Nehru and his military advisors began to work on a contingency plan for a major offensive.44 Though this first step towards working with and through international institutions was involuntary, Nehru would eventually come to embrace these institutions, and they would in fact become the core of Nehruvian international thought which would come to guide the Indian approach to Kashmir in this first phase. Pakistan, during the lull, began to shift its strategy away from the offensive. Once it became clear that the Pakistani-Kashmiri militia was greatly outmatched by the Indian army, the new strategic objectives were to make the expulsion of the Pakistani-Kashmiri militia, which Pakistani strategists had begun to see as the eventual scenario, as difficult and expensive for India as possible, to hold as much of the gained territory as possible, and to stop the Indian army from entering Pakistan at all costs.45

28 Ian Copland, “The Princely States, the Muslim League, and the Partition of India in 1947”, The International History Review, Vol. 13, No. 1 (Feb., 1991), pp. 38-69. P. 38-9.

29 Praveen Swami, India, Pakistan and the Secret Jihad: The Covert War in Kashmir, 1947-2004, (New York: Routledge, 2007), P. 15.

30 Shuja Nawaz, Crossed Swords: Pakistan, Its army, and the Wars Within. (Oxford: Oxford University Press, 2008). Pp. 40-42

31 Swami, India, Pakistan and the Secret Jihad, P. 15.

32 Ibid, Pp., 42-43.

33 Ibid, P. 43.

34 Ibid, P. 43.

35 Swami, India, Pakistan and the Secret Jihad, P. 15-16

36 Ibid, Pp.18-22.

37 Nawaz, Crossed Swords, P.49.

38 S. Paul Kapur, “India and Pakistan's Unstable Peace: Why Nuclear South Asia Is Not like Cold War Europe”, International Security, Vol. 30, No. 2 (Autumn, 2005), pp. 127-152. P. 136.

39 Swami, India, Pakistan and the Secret Jihad, Pp. 21-23.

40 Ibid, P.22.

41 Ibid.

42 Ibid, P. 22.

43 Nawaz, Crossed Swords, P. 50.

44 Swami, India, Pakistan and the Secret Jihad, Pp. 22-23.

45 Nawaz, Crossed Swords, P. 57.

I simply wanted to thank the mods for another exemplary job in this highly-partisan discussion. I had minimal info of this situation going in, and I feel more informed about the issue. There was little inflammatory rhetoric and plenty of substance throughout. Thank you once more,as a reader of this sub.