They haven't been exactly friends. They are now.
Volen Siderov, perhaps Bulgaria's most scandalous extreme nationalist, whose rabid xenophobic and anti-Semitic rhetoric dwarfs everyone in the Le Pen family combined, had a birthday recently. His guests of honour: GERB's top brass – Boyko Borisov and Tsvetan Tsvetanov.
Since they got the power in 2009, both Borisov and Tsvetanov have been careful not to irritate the West. They have been more than willing when it comes to police cooperation, counterterrorism and preventing illegal immigration, which after all is what the West is primarily interested in these days. In exchange, they have been given a free hand to do whatever they feel like in their native Bulgaria. Which they have done: the result of which is a dismal economy, lowest ever freedom of speech, uranium traces in the drinking water supplies for Haskovo and a Sofia where the only thing that really functions is the car removal trucks drivers lovingly refer to as "spiders." Obviously, the
West doesn't care about these things, but it does care if someone like Siderov gets to talk.
After the latest general election, however, Siderov will talk. He will be a major, in fact an indispensable coalition partner to the new GERB government, which a media in Sofia recently described as More of the Same, With a Pinch of "Patriotism."
Interestingly, when GERB were briefly out of power in 2013, the street protestors, the intellectuals and GERB itself made a big fuss about having Volen Siderov support the Oresharski government. The fact is that he did not. He just attended a session of parliament to make sure there was a quorum. At that time, everyone was outraged that the BSP could partner with people like Siderov.
No one seems to care in 2017, so happy birthday!