Eurovision — the annual Continentwide song contest that is sort of like “American Idol” shot through with nationalist strife — is a breeding ground for controversy year after year, and 2017 is no exception.

On Thursday, Eurovision announced that Russia “will no longer be able to take part in this year’s competition.” This came after Russia expressed indignation that Ukraine, this year’s host, had barred Russia’s contestant, Yulia Samoylova, from entering the country to compete because she had once visited Crimea, the Ukrainian region that Russia annexed in 2014.

Russia’s Eurovision broadcaster, Channel One, refused to send a replacement, let her participate via satellite or even broadcast the show.

It’s the first time that a host country of the singing contest has barred another nation’s participant. And the clash of geopolitics and pop culture raises the question: How did it come to this? Here’s a rundown.