the Libertarian philosophy is that the purpose of government was expressed in the Declaration of Independence: It is to secure these rights (life, liberty, and the pursuit of happiness) that governments are instituted among men.
Any law, therefore, that doesn't protect our liberty is a bad law. Government actions that don't serve to protect our liberties are not necessary.
Neither the Democrats nor the Republicans follow a philosophy like that. Both are all about increased government authority and less individual liberty.
yes, parties have effectively steered government away from what the people wanted mainly by means of keeping the public fat dumb and happy. works pretty well at least for a while. see the collapse of the roman empire for the eventual termius.