MEMORY has long been the subject of fierce and often deadly ideological battles in Russia. Those who control the past also control the present. Following the murder of Boris Nemtsov, a liberal opposition leader, on a bridge by the Kremlin, a fight for his memory, and for the Russian flag, is taking place. In Soviet times, purged Communist Party members were excised from photographs as though they never existed. Now it seems the Kremlin is trying similarly to airbrush Mr Nemtsov.

First Kremlin spin-doctors tried to divert attention from Mr Nemtsov’s murder to the “sudden” disappearance of Vladimir Putin, Russia’s president. Ten days later, Mr Putin re-emerged triumphantly and celebrated the anniversary of Russia’s annexation of Crimea at the spot where Mr Nemtsov died. A frenzied crowd yelled “Ross-i-ya”, as if that could quash memories of Mr Nemtsov and his opposition to war in Ukraine.

In the middle of the night on March 27th, a month after Mr Nemtsov’s murder, the authorities cleared the bridge of flowers and photographs. Thanks to Mr Nemtsov’s friends and followers, the memorial was restored. People across the country ordered flowers online, and supporters took them to the bridge. Mr Nemtsov’s photographs under Russian tricolours have been remounted on the balustrade. Volunteers guard the memorial day and night in snow and rain, sustained with tea and food by ordinary folk. They will not go away; they are being true to Mr Nemtsov’s spirit.

He managed to stay in politics despite state propaganda labelling him a “foreign agent” and “fifth column”. But fighting Mr Nemtsov after his death may prove even harder than it was during his life. Groomed to be Russia’s liberal president by Boris Yeltsin, the charismatic, honest Mr Nemtsov could turn into a symbol of Russia’s unfulfilled promise. The display of Russia’s national flag next to his name should be particularly troubling for the Kremlin.

The bridge has already been dubbed Nemtsov Bridge. It could now become a focal point of liberal opposition to a brutal regime, a role that after 1991 was played by the White House, then the seat of the Russian parliament. The Kremlin will try to clear the bridge of traces of Mr Nemtsov’s murder. But the harder it tries, the more resonant the spot will become.