The return of Taliban rule after 20 years will likely produce the typical mayhem and murder when a regime suddenly collapses. Longer-term, immense challenges face the people of Afghanistan under the "Islamic Emirate" and, externally, the takeover will intensify a host of international military, security, political and humanitarian problems.

But much is also at stake for world Islam, a crucial aspect that the media have tended to slight thus far, as tmatt has already observed here at GetReligion. Journalists may be witnessing a new phase in what Georgetown University expert John Esposito has called a long-running "struggle for the soul of Islam."

The fallout could last for years, or even a generation, because it will be highly difficult to again dislodge Taliban control — from within or without. Though plans are unknown, Afghanistan’s rulers may well reimpose harsh practices that had provoked widespread condemnation (without, however, losing religiously freighted diplomatic recognition by Saudi Arabia). And they could again provide a strategic national sanctuary from which terrorists could target innocent civilians in the despised West.

The key, of course, is that all this would be proclaimed as God's will, enacted in the name of Islam and for its benefit. The Taliban announce religious zeal for a strict construction of Islam's dominant Sunni branch in their very name, which derives from "student" in the Pashto language.

Militant movements that include the Taliban have achieved special appeal for youthful Muslim devotees and some government backing. They have variously claimed religious sanction for destruction of historic artifacts, torture, mutilation, beheading and stoning to death, execution without trial, kidnaping for ransom, forced marriages and sexual slavery, drug trafficking and thievery, killing of envoys and charity workers, and persecution not only of Christians and Jews and Yazidis but even moreso of fellow Muslims who dissent (see scholar Paul Marshall’s book “Silenced: How Apostasy and Blasphemy Codes are Choking Freedom Worldwide“). Not to mention banning music and movies, kites and dolls.

The most severe consequences have fallen upon Muslim girls and women, not merely put under strict clothing mandates, but denied human rights, education beyond age 10 or careers outside the home.