TO THE untrained eye, the activity looked innocent enough. Patriotic Kazakhs marked a public holiday in March by displaying balloons of the same turquoise colour as the national flag. The hitch was that Mukhtar Ablyazov, an exiled oligarch, had urged citizens to display turquoise balloons to demonstrate their support for his political movement, Democratic Choice of Kazakhstan (DVK by its Russian acronym), which a Kazakh court had banned days before as “extremist”. It was unclear how many of the balloon-flaunters even knew about Mr Ablyazov’s call. But the police concluded that it was safest to haul them in for interrogation, just the same. After all, Nursultan Nazarbayev, the 77-year-old strongman who has ruled this oil-rich Central Asian state for nearly three decades, tolerates no challenge, however trifling, to his autocratic rule.

Mr Ablyazov first angered Mr Nazarbayev in 2001 by founding a reform movement. He was soon jailed on corruption charges, then pardoned and released. In 2009 he ran into trouble again, fleeing Kazakhstan for London as the state seized his bank, BTA. Mr Ablyazov, who was accused of massive embezzlement by the new management of BTA, suffered several adverse rulings in British courts before going on the run after a judge ordered him jailed for contempt of court. He was captured in 2013 in a dramatic swoop on a mansion on the French Riviera, and spent over two years in a prison in Paris battling extradition to Russia to face corruption charges. Mr Ablyazov won a triumphant victory in 2016, when a French court ruled that Russia’s request was made on Kazakhstan’s behalf, for political reasons. The gleeful oligarch emerged from jail pledging to overthrow Mr Nazarbayev.

Mr Ablyazov’s political battle is waged mainly virtually—hence the Kazakh government’s occasional threats to block popular social networks and messaging apps including Facebook, Twitter, Instagram and Telegram. The Kazakh authorities hunt relentlessly for DVK supporters inside Kazakhstan. Amnesty International has declared one young woman, Akmaral Tobylova, a prisoner of conscience. Ms Tobylova, who is pregnant, was held under house arrest for a month after looking at DVK’s website, and now faces charges of financing an extremist group.

Mr Ablyazov’s appeal in Kazakhstan appears limited, though he enjoys notoriety at home because of the government’s constant denunciations. He has been accused, among other things, of inciting unrest among oil workers in 2011 (when 15 civilians were shot dead by security forces) and ordering the killing of a business partner. Mr Ablyazov rejects all the accusations as politically motivated smears.

In theory, Kazakhstan has legal opposition parties, but they are only for show. One of them, Ak Zhol, is led by a former member of the ruling party, Nur Otan. One of Mr Nazarbayev’s opponents in the presidential election of 2011 admitted that he was not planning to vote for himself, but for the “Leader of the Nation”, as Mr Nazarbayev is known. Alga!, another Ablyazov-backed movement, was banned in 2012, when its leader Vladimir Kozlov was jailed on spurious charges of seeking to overthrow Mr Nazarbayev.

At the most recent presidential election, in 2015, Mr Nazarbayev won 97.75% of the vote, in a three-way race. The election had originally been scheduled for 2016, but parliament pulled it forward by a year. In the initial vote on the rescheduling, one member of the upper house appeared to vote against. But officials later explained that he had simply pressed the wrong button. They re-held the vote, which was unanimously in favour. Whether the briefly dissenting senator possessed any turquoise balloons is not clear.