Previously, the primary means of protecting individuals was to limit government intervention in their lives. Today is the era of aggressive industrial capitalism, the government seems to be the only way to protect the individual from selfish economic system. Liberals who once saw the government as a source of tyranny had to learn to love him as a protector of their liberties.

What exactly is the perspective of this source

Based on the information provided, the perspective of this source appears to be an acknowledgment of a shift in perspective regarding the role of government in protecting individuals. It suggests that in the past, the primary means of protecting individuals was seen as limiting government intervention in their lives. However, the source suggests that in today's era of aggressive industrial capitalism, the government is seen as the only way to protect individuals from a potentially selfish economic system.

Furthermore, the source highlights that liberals, who were once skeptical of government intervention and saw it as a potential source of tyranny, have had to adapt to the changing circumstances and embrace the government as a protector of their liberties. This indicates a shift in their perception, as they come to see the government as a necessary safeguard against potential exploitation and inequalities that can arise in an unfettered capitalist system.

It's important to note that this explanation is based on the limited information provided and the context may differ in a more comprehensive analysis of the source.