Strangely enough, the economic approach favored by today's conservatives is called "neo-liberalism". It developed out of a fundamental misinterpretation of Adam Smith's original concepts of liberalism in economics.
By misinterpretation I mean that today's conservatives leave out a basic concept which is the centralizing force behind Smith's economics: moral control. He made the same academic error in the 18th century that Marx made in the following century; he assumed a basic morality in humans which would make the need for government intervention unnecessary in the face of excess and abuse. In Smith's case morality or virtue derived from the operation of God in earthly affairs while Marx derived it from the evolution of human nature.
The Liberal of the 21st century long-since threw off notions that government intervention in economics is by definition a bad thing. The modern Liberal knows that the when modern Conservatives use the phrase "invisible hand" what they really mean is only "the finger". Where Smith defined "rational self-interest" in terms which included a balance between the individual and the society in which the individual lives in a manner which today's adherents to Smith almost entirely ignore.
Experience in the real world teaches Liberals that the rationality of Smith and the moral evolution of Marx don't play enough of a role -- to the extent that they even exist -- to properly temper the drive to excess that human economic behavior so often unleashes.
Modern Conservatives cling to the mythical notion of inherent human kindness. Liberals hope for and encourage it wherever possible, but prefer to find a means to account for the failings of such a hope. In Democratic societies, where the people as a whole express their need for social control, the surest means of tempering the economic excesses of individuals falls to their government. The amount of control exerted varies from state to state and how well it functions is as variable as the personalities of every individual in the society, but the alternatives are found wanting. But that is a topic for another post (which hopefully will occur before another 3 years pass...)