Watershed moments in Afghanistan happen by stealth. Last weekend — the anniversary of the Soviet invasion 32 years ago — President Hamid Karzai rid himself of his most outspoken critic, a prominent official with one of the few government institutions in Afghanistan that actually performs well — the Afghanistan Independent Human Rights Commission. The move, announced Thursday, seems intended not only to silence a critic but bury the truth about the crimes of the past.

Why now? Ahmad Nader Nadery had anticipated losing his job — he, together with his colleague Ahmad Fahim Hakim, also dismissed, has been a thorn in Karzai’s side for many years. Both had campaigned tirelessly against human rights abuses and electoral fraud. But this sudden move, scheduled while most of the West is on holiday, has a more ominous intent.

For the past several years, Nadery has been heading an effort to document war crimes going back to the time of the Soviet invasion. That effort is nearly done, and the long-anticipated report was scheduled to be released soon. Karzai’s move seems designed to smother the report before it sees the light of day.

Talking about the past has never been popular with the Afghan government or its U.S. ally. Karzai’s cabinet includes Vice Presidents Marshal Muhammad Qasim Fahim and Karim Khalili. Both men have been accused of war crimes in international human rights reports. U.S. State Department officials also have been nervous about the coming report, concerned that the release of details of Taliban atrocities in the late 1990s could upset delicate negotiations to get peace talks underway. “Now is not the right time,” one U.S. official recently told me. The Americans fear rocking the boat just at the moment they are trying to hammer down a deal — and leave.