EVER since a plane carrying then-president Lech Kaczynski crashed near the Russian city of Smolensk on April 10th, 2010, killing all 96 people on board, Poland’s Law and Justice party (PiS) has been consumed by conspiracy theories. Now in power, it is led by Jaroslaw Kaczynski, the late president’s twin brother, who believes that Russia brought the plane down—perhaps with the connivance of PiS’s Polish political enemies. So the government is having the bodies exhumed. An international team of experts will examine them for evidence of foul play. Many of the victims’ families do not want their relatives dug up, but they have been told the choice is not theirs to make.

The move does not seem to be prompted by political need. PiS is very popular, largely because of its generous welfare policies, including a lavish monthly child benefit it introduced. According to the most recent poll, just 27% of Poles believe the conspiracy theories about the crash. But the Smolensk issue is important to PiS’s core electorate, mostly older people outside the big cities.

Earlier this year Poland’s defence minister, Antoni Macierewicz, who claims that the plane disintegrated before crashing, announced that a new investigation was being launched. Mr Kaczynski has repeatedly insinuated that his nemesis Donald Tusk, the former leader of the centrist Civic Platform (PO) party who was prime minister at the time, was somehow involved in the crash or in a subsequent cover-up. Mr Tusk is now president of the European Council; last month Mr Kaczynski hinted that Warsaw may not back him for a second term in May.

Advocates of the exhumation point out that a fresh autopsy of Poland’s wartime leader Wladyslaw Sikorski in 2008 debunked theories that he was assassinated. (One PiS MP noted that delayed autopsies are often useful, citing the archaeological examination of the Pharaoh Tutankhamun.) But just 10% of Poles support the exhumation. Relatives of some of the victims are aghast. Over 200 signed a letter opposing it. One widow expressed despair at having to see her husband’s corpse dug up to prove “the existence of an attack that I do not believe in”.

The letter has had little effect. The sarcophagus of Lech Kaczynski and his wife Maria, buried in the crypt under the Wawel castle in Krakow, will probably be opened this month. More exhumations will follow. Meanwhile, a Polish feature film released this autumn, “Smolensk”, depicts a sceptical journalist becoming convinced that the rumours are true. It includes footage of Mr Tusk deep in conversation with Vladimir Putin. At the premiere, Mr Kaczynski said the film “simply depicts the truth”. It does not, but in a world where the boundaries between fact and fiction are increasingly ignored, that may not matter much.