FIRST the crime, then the lie. After the massacre in April 1940 of 20,000-plus captured Polish officers by Stalin’s NKVD secret police, during the Nazi-Soviet carve-up of Poland, came five decades during which the Soviet Union blamed it on the Germans. Russian media still sometimes peddle Soviet lies, mostly amid official silence. The files are sealed. Victims’ relatives are suing Russia in the European Court of Human Rights.

But now Russia’s prime minister, Vladimir Putin, has invited his Polish counterpart, Donald Tusk, to attend a ceremony on the 70th anniversary of the massacre at its site, in Russia. That matters: Russian television viewers will for the first time see their leaders publicly accepting the true story.

The phone call followed two years of patient diplomacy by the soft-spoken Mr Tusk, who has created a rapport with Mr Putin. Notably, he brought the Russian prime minister last September to an event in Gdansk marking the 70th anniversary of the outbreak of war. That was tricky. Like many Russians, Mr Putin prefers to commemorate the tens of millions of Soviet war-dead than to be reminded that the Soviet Union and Nazi Germany were allies before they were foes. But the event went smoothly.

Poland’s foreign minister, the once-hawkish Radek Sikorski, is being similarly canny. He has asked a predecessor, Adam Rotfeld, to get Russian and Polish historians to find consensus on the facts. Stanislaw Budzik, a senior Polish bishop, has been mending fences with Russia’s Orthodox church. Some Orthodox monks visited Czestochowa, Poland’s holiest Catholic shrine, last year. During the war their monastery was used to intern 6,000 Poles who were then killed by the Soviets. The monks want to build a commemorative chapel.

Along with Orthodox and Catholic leaders, senior Jewish figures may attend a religious ceremony at the Katyn site in September. Among the many hundreds of Jewish officers and reservists murdered was Baruch Steinberg, the chief rabbi of the Polish army.

Poles may sense a sell-out: Mr Putin’s language at Gdansk last year fell short of the kowtow that some desire; it may be the same at Katyn. But the thinking in Warsaw is that rubbing Russian noses in past crimes and demanding compensation has proved fruitless. A softer approach may work better.