Six months from now, barring a major change of heart by the despotic President Islam Karimov, US troops and materiel will withdraw from southern Uzbekistan, and one of the most delicate chapters of post-9/11 history will come to an end. At that point a new chapter will begin for a country whose leader has lost the plot.

Easy but flawed conclusions are already being drawn from Mr Karimov’s testy decision to end US use of the Karshi-Khanabad, or K2, base to which he granted Washington access days after the September 11 atrocities. Will it mean the loss of a key staging post in the war on terror? On a purely logistical level, yes. The K2 base has been home to at least 1,300 US troops for most of the past four years. Initially used for bombing raids on al-Qaeda camps in Afghanistan, it has since grown in importance as a distribution point for aid. But will the American withdrawal amount to a strategic victory for Russia in its old Soviet underbelly, or a diplomatic coup for China, which, likewise, is seeking to deepen its influence throughout Central Asia? Hardly.

The “Great Game” that was played out across this largely unconquerable region in the late 19th century was for trade routes, natural frontiers and the allegiances of the tyrants who controlled them. If that was a zero-sum game, the 21st-century version now under way emphatically is not. The US is playing for democratisation and progress against terrorism, not a geographical sphere of influence, and it has alternatives to K2. Despite what the Pentagon rightly sees as Russian and Chinese “bullying” of Central Asia’s former Soviet republics, Kyrgyzstan and Tajikistan have agreed to continued US use of their airspace and territory. US (and British) forces also, of course, have the use of the Bagram airbase outside Kabul.

“We’re always thinking ahead,” Donald Rumsfeld, the US Defence Secretary, said with some justification after touring the region last week. “We’ll be fine.” Even more importantly, it will no longer be possible even for habitual critics of US foreign policy to accuse Washington of complicity in Mr Karimov’s lamentable record on human rights. On the contrary, the ending of the K2 base deal was triggered by fierce American condemnation of the massacre of unarmed civilians by Uzbek security forces in Andijan in May, and by US support for the evacuation to Romania last week of refugees who had been hiding in neighbouring Kyrgyzstan. Mr Karimov had demanded their return.

This former Politburo strongman has wrecked Uzbekistan’s economy and the lives of countless thousands of its citizens in the 14 years since independence. China’s new show of support for him is as ill-advised as its welcome last week for Robert Mugabe. Russia, similarly, risks repeating its mistake in Ukraine of backing a deeply unpopular figure for narrow strategic reasons. When regime change comes to Tashkent, as eventually it must, ordinary Uzbeks will thank neither of their giant neighbours.