The closest that Bulgaria came to serious civil disorder was during the 1997 crisis after a banking collapse helped lead the economy into a period of hyperinflation. (If you've never lived through an episode of hyperinflation...well...it's a trip. You sit down in a cafe and while you drink your coffee the exchange rate at the exchange bureau across the street changes twice.)

Mostly peaceful street demonstrations forced a less-than-competent and widely-perceived-as-corrupt BSP government to wisely call new elections which were won by the Union of Democratic Forces (the broad anti-communist opposition). The UDF government (1997-2001) instituted a currency board that stablized the Bulgarian lev by pegging it to the Deutschmark (now the Euro) and did much to clean up organized protection rackets masking as "insurance companies."

Simeon's Movement came and upset the relative bipolar political atmosphere by walking away with half the seats in parliament...just shy of a majority. This government (2001-2005) has largely continued the previous economic policies. The failure of the UDF to win these elections plus some personality differences within the UDF led to its splitting into three political formations. The UDF-core is likely to be the third largest party in parliament.