1947–48, 1965, 1971
From the time of India’s independence from Britain, the Muslim and Hindu elements of this former colony have been in conflict. Pakistan has traditionally been on the losing end of these conflicts, but has relied on US and PRC support to maintain military credibility against a more robust Indian defense capability.
Time: Early War
Removed after event: No
A huge threat in the early game: this is one of those cards that always seems to work for your opponent, but never yourself. (See also Brush War.) Like Truman Doctrine/Warsaw Pact, the deterrent threat of the Indo-Pakistani War is perhaps the strongest aspect of the card, and makes Afghanistan considerably more attractive (not that it wasn’t attractive already: it borders the USSR, it’s the easiest non-battleground for the USSR to grab for Domination, and the US can use it to block the USSR from Pakistan as well as the +1VP).
Usually you’ll just have to chance the roll while moving east from Iran: shoring up both Afghanistan and Iran before going into Pakistan is not a bad idea, but still leaves you with a 1/6 possibility of disaster. India is even more perilous: it’s a huge pain to get to Burma first and then get India, and even if you lock down the whole region, India is never safe (unlike Pakistan). It’s usually therefore a good idea to contest Burma a little in the Early War: not only is it 1VP when Southeast Asia Scoring comes out, but it also increases the chance that you can steal India.
The other big threat of the War isn’t even the loss of the country; it’s the loss of access. If you play into Pakistan and control it, losing the Indo-Pakistani War will also cut you off from India. So if you’re very concerned about the Indo-Pakistani War, you can play a single influence into Pakistan first. This way even if you lose the War, you can still take over Pakistan. Your opponent will be able to play into India first and likely take it over, but it’s better than losing Pakistan and being blocked out of India.
The US will tend to play Indo-Pakistani War more than the USSR in the Early War. This is for two reasons: one, the USSR is more likely to be in Pakistan/India than the US, and two, the US has a more difficult time collecting Military Operations. Indo-Pakistani War is therefore tantamount to at least +2VP (or possibly +4VP) when no other source of Military Operations is available. Of course, Early War Ops are precious, but 2VP for 2Ops is quite tempting, and the possibility of another 2VP and a crucial battleground makes it even sweeter.
As USSR, drawing Indo-Pakistani War makes life a whole lot easier. It means you can spread directly east in a straight line without having to detour into Afghanistan. This means you make it much farther into Southeast Asia than you otherwise would if you had to stop to defend against a possible Indo-Pakistani War. (This is true of US as well, but US is usually just grateful enough for even the opportunity to play into Pakistan.)
After the Early War, the region is usually sufficiently locked down that the Indo-Pakistani War has little chance of changing anything, and you can usually get the Military Operations elsewhere. But in the event of some sudden change in the region (e.g., Brush War, Ussuri River Skirmish), the Indo-Pakistani War can be an ace in the hole: if the US can somehow flip Pakistan, India is suddenly looking a lot more vulnerable.