Pakistan recently announced a change in the how they recruited troops for their 480,000 man army. They want more troops that are Baluchi or Sindi, or non-Moslems, to make the army ethnic composition more like that of the population as a whole. But the real reason may be to reduce the number of Pushtuns in the army. The generals have been increasingly concerned about the loyalty of some Pushtun troops, considering the large number of Pushtuns involved with Islamic radicalism (particularly the Taliban, which is almost entirely Pushtun). The current composition of the army is of Punjabis- 55.8 percent, Pushtuns- 15.4 percent, Baluchi- 2.3 percent, Sindis- 15.1% and those from Pakistan controlled Kashmir and the nearby Gilgit-Baltistan region- 8.5 percent. While three percent of Pakistanis are non-Moslem, only 0.43 percent of the army is.
The Pushtun tribes comprise 15 percent of the population, but they are also the poorest and least educated minority. A unique feature of Pakistan is that it's 165 million people are all minorities, although the Punjabis (44 percent of the population) are the dominant one (not just in numbers, but in education and income as well). Closely allied with the Punjabis are the Sindis (14 percent), and together these two groups pretty much run the country. Karachi, the largest city in Pakistani, is in Sind, but contains residents from all over the country. Then there are Seraikis (10.5 percent, related to Punjabis), Muhajirs (7.6 percent, Moslems who came from India after 1947), Baluchis (3.6 percent) and other minorities amounting to about five percent. The Seraikis and Muhajirs live in Punjab and Sind.
The lowland people have not been able to govern the Pushtun and Baluch tribes up in the hills. This has been a problem for thousands of years. The hill tribesmen are fearless warriors, but the lowlanders are more numerous, disciplined and, in the end, more than a match militarily for the tribes. The hill people can threaten and raid, but they can't conquer. The tribes will risk, and often endure, extermination, rather than submit to rule by a king or nation-state. That is slowly changing, but it will be generations before the tribal loyalties are replaced by national ones. The Pushtun and Baluch are not unique in this respect. European tribes went through a similar process centuries ago, and there's an ample written record describing it. But the European tribes didn't have the Internet, modern weapons and international terrorism at their disposal. There are a lot of tribal cultures left on our planet, and most are pretty much left alone, to evolve at their own pace. But when tribes declare war on the world, it can become a problem that the world has to deal with.