- To protect our rights, and
- To provide public resources
The "protect our rights" part includes government functions such as the criminal justice system, the civil justice system, and the military.
The "provide public resources" part includes roads, public transit, schools, libraries, parks, and public health. It also includes safety net programs, social insurance programs, and public hospitals.
If the police saw their job as "protecting citizen's rights" instead of "enforcing the law", the officers would conduct themselves differently, they would be seen differently by the community, and we would not have the sort of policing issues that are making headlines today.
If the federal government saw the military's role as "protecting citizen's rights" it would surely reduce the frequency of their deployment. It could, of course, be expanded to include protecting all people's rights, but that's something that we should only undertake in concert with our international partners, not something we should pursue on our own.
"Providing public resources" is more commonly the area of disagreement because no matter the resource there will be people who don't derive a direct benefit from it and therefore don't support it. Also, while our rights can, at times, be seen as absolute, it is reasonable to set limits on public spending for parks, libraries, and safety net programs and people will have differing opinions of what those limits should be.
Generally speaking, people agree on this view of the duties of government. There are some on the fringes - anarchists at one end and authoritarians at the other - who disagree, but they lack both the numbers and the pragmatism to be taken seriously.
Where people disagree comes down to the decision about where to draw the line - in both the protection of rights and the provision of resources. First asking if the job qualifies as a government responsibility and second on what resources to dedicate to it. That's essentially the narrow range of difference in American politics: how much should the government take on and how much should the government leave to people to resolve for themselves. Personally, I believe that the government that governs least governs best, and I support a minimal government. Of course, what I perceive as minimal is a lot more government than some people support.
I choose to employ a three part test:
- It has to serve the common good.
- It has to be something that people cannot do for themselves.
- It has to be something that cannot be entrusted to private interests.
All three must be true for the government to take on the job.
For example: National Defense. It serves the common good for us to have a national defense. That way we don't get conquered and occupied by a foreign nation that would not defend our rights. The people cannot do it for themselves. Even if everyone were issued weapons, that would not constitute an effective national defense. And it is not something can be entrusted to private industry - just imagine if our foreign enemy outbid us for their services. So national defense passes the test and is an appropriate task for the government.
There are a number of other government activities which likewise which enjoy broad (though not universal) consensus as appropriate: police, Courts, jails, roads,
People will certainly argue what does or does not serve the common good. The invasion of Iraq? The auto industry bailout? The financial bailout? Whatever it is that the Department of Commerce does?
People will argue about what people can or should do for themselves. Do we need OSHA to set regulations for worker safety or can that be negotiated between employers and employees? Do we need the FDA to regulate the wholesomeness of food and the effectiveness of drugs or will the market resolve problems and remove bad actors?
And, finally, there will be differences over what can or cannot be outsourced - should the government hire doctors for Medicare, Medicaid, and the Veteran's Administration, or simply act as the paying agent? Should the government operate schools or contract with private entities to teach our children? Should the government have workers on staff to fill pot holes or contract that work out to private companies? Should security in The Green Zone be provided by the US Army or by Blackwater?