The Wrong Enemy: America in Afghanistan, 2001–2014 by Carlotta Gall Houghton Mifflin Harcourt, 329 pp., $28.00

During the Afghan elections in early April I was traveling in Central Asia, mainly in Kyrgyzstan. I wanted to inquire into the fears of the governments there as a result of the US withdrawal from Afghanistan. What did they think of the growth of Taliban and Islamic extremism in Afghanistan and Pakistan? Officials in each country cited two threats. First, the internal radicalizing of their young people by increasing numbers of preachers or proselytizing groups arriving from Pakistan, Bangladesh, and the Middle East. The second, more dangerous threat is external: they believe that extremist groups based in Pakistan and Afghanistan are trying to infiltrate Central Asia in order to launch terrorist attacks.

Islamic extremism is infecting the entire region and this will ultimately become the legacy of the US occupation of Afghanistan, as the so-called jihad by the Taliban against the US comes to an end. Iran, a Shia state, fears that the Sunni extremist groups that have installed themselves in Pakistan’s Balochistan province on the Iranian border will step up their attacks inside Iran. In February Iran threatened to send troops into Balochistan unless Pakistan helped free five Iranian border guards who had been kidnapped by militants. (The Pakistanis freed four of the guards; one was killed.)

Chinese officials say they are particularly concerned about terrorist groups coming out of Pakistan and Afghanistan that are undermining Chinese security. Although China is Pakistan’s closest ally, its officials have made it clear that they are closely monitoring the Uighur Muslims from Xinjiang province, who are training in Pakistan, fighting in Afghanistan, and have carried out several terrorist attacks in Xinjiang.

Terrorist assaults from Pakistan into Indian Kashmir have declined sharply since 2003, but India has a perennial fear that Islamic militant groups based in Pakistan’s Punjab province may mount attacks in India. Many Punjabi fighters have joined the Taliban forces based in Afghanistan and in Pakistan, and they have attacked Indian targets in Afghanistan. India is also wary of another terrorist attack resembling the one that took place in Mumbai in 2008.

For forty years Pakistan has been backing Islamic extremist groups as part of its expansionist foreign policy in Afghanistan and Central Asia and its efforts to maintain equilibrium with India, its much larger enemy. Now Pakistan is undergoing the worst terrorist backlash in the entire region. Some 50,000 people have died in three separate and continuing insurgencies: one by the Taliban in the northwest, the other in Balochistan by Baloch separatists, and the third in Karachi by several ethnic groups. That sectarian war, involving suicide bombers, massacres, and kidnappings, has gripped the country for a decade.

Some five thousand Pakistani soldiers and policemen have been killed and some twenty thousand wounded, both as targets of terrorist attacks and during offensives against them. The…