Russia had two revolutions in 1917. In the first one, pretty much everyone who mattered was unhappy with the regime. After some clashes between protesters and internal security forces, the emperor abdicated. A provisional government formed by established politicians took control, but it had to share power with workers' councils. The country became fragmented.

The provisional government was center-left, the army was mostly controlled by the right, and the workers' councils leaned towards revolutionary left. The right wanted to use the army to arrest Bolshevik leaders. The government declined, fearing a military coup. The right saw the government siding with the left and made an actual coup attempt. The government had to rely on the workers' councils to stop it. Which then emboldened the Bolsheviks to stage a revolution of their own a bit later.

But because the right was definitely not on board this time, the second revolution was only partially successful. Instead of a controlled regime change, the Bolsheviks got a civil war that lasted five years and killed millions.