The US government is an insurance company with an army."

The quote in the title originates with Bush treasury official Peter Fisher.  In some ways, the army also serves an insurance function.  It is also ostensibly there to reduce the risk of violence and invasion.  When you look at what government spending is for, most of it is to reduce risk (insurance) and most of the rest of it is to invest in future productivity.  Education and infrastructure are investments and otherwise, the government mainly spends money on health, pensions, defense, and income security (welfare & disability). 
The purpose of government is to fix market failure, and the main fix the median voter wants is to reduce risks.