To take the extreme version of this failure to appreciate what is at stake in acts of government, take the libertarian model of government as a collection of enterprises, modelled on or constituted by private companies. This model is a product of view that private enterprises in competitive markets are, in certain rather common circumstances, extremely effective distributors of resources. There are two problems here. The first is that many of the traditional tasks of government are in circumstances where markets are very bad at distributing resources - healthcare is the stand-out example (here's one summary, and another), the same counts for extremely large projects the benefits of which are dispersed very widely, like transport and communication networks, or emergency response agencies, or monitoring programmes (a summary).
But let's concentrate on the second problem: that something a government has that no company has is a jurisdiction where it can compel a range of otherwise independent agents to co-ordinate. Take the laughably stupid suggestion of Ron Paul's to privatise the FAA or the TSA. These agencies don't perform consumer services, they are regulatory agencies. Some people might say that the TSA used to be in effect a series of private security companies and contractors before Homeland Security came along and emnployed them as federal agents, but that's wrong. The creation of Homeland Security didn't just change who writes the paychecks - it created a central co-ordinating authority. Homeland Security and its analogues have powers that no security firm has. I don't mean powers like 'now TSA has the power to force you to either receive a pat-down search or go through the body scanner'. I mean power as in capacity - there are things governing agencies can achieve that no alternative could. TSA decides that nobody can go through a US airport with certain liquids in carry-on luggage, and boom, it's done (given the resolution is enforceable, and not just a dead letter). Now every airport in the domain follows that resolution, and nobody goes through with certain liquids in carry-on. If the TSA was replaced with a series of security companies, a policy like that could extend only as far as the individual companies did. For the market to work effectively, there would have to be a variety of these companies (if there was a monopoly, it would be just like a government, but worse in every regard). Which means that there could be no resolution enforced across an entire domain.
You might not care about what goes in people's carry-on luggage, but the same point carries over to any government action. When slavery got banned by the UK, they were able to stamp out the intercontinental slave trade almost immediately because of the blanket prohibition on it across sovereign British territory (including large parts of the Atlantic). If slavery wasn't banned across the whole domain, individuals could have gained an economic advantage by continuing to use it while people around them don't, and as they took over more of the market slavery would then be reintroduced. This is how it is in general for regulation - there is no way for there to be any kind of competition among regulations, because a regulation isn't a regulation unless it is an uncontested authority over its domain. Similarly, a government can't co-ordinate without authority, and we need that co-ordination for goods like healthcare, transport networks, the maintenance of certain societal standards, etc.
(First aside: The above is one of the reasons the US's widespread use of security contractors in warzones is so pernicious - in practice it has meant that these security firms have all of the authority of the governmental agencies that back them, but none of the controls placed on the government.)
(Second aside: There is another effect of this observation, regarding another lamentable shortcoming in a lot of public debate. Often when questionable market practices are pointed out - working conditions in China, financiers reneging on promises not to fund certain types of industry, etc. - the response comes that attempts to regulate this domain would be self-defeating, since there are agents outside the domain who will continue on regardless (here's an example). This is no comment at all about the desirability of the regulations. It's a comment on how far the jurisdiction of the regulators go. If we took this seriously as a reason not to have regulations, then we couldn't have any regulations whatsoever, and every domain would become a race to the bottom.)
The above is a comment on what is involved in something being a government. It shouldn't be read as a comment on the desirability of any particular system of government, or even of which domains a co-ordinating authority like described above is needed - the above is a schema that applies to all systems of government. It applies even to anarchists in the tradition of Proudhon and Kropotkin, who want extremely direct and reconstructed forms of governmental authority. It doesn't apply to libertarian model canvassed earlier, because as discussed that isn't a theory of government proper. It does apply to serious thinkers like Hayek and Nozick during his libertarian phase (they just think authorities like described above should have extremely limited domains), but Ron Paul bears as much resemblance to them as he does to the Emperor of Japan.
The above is a comment on what is involved in something being a government. It shouldn't be read as a comment on the desirability of any particular system of government, or even of which domains a co-ordinating authority like described above is needed - the above is a schema that applies to all systems of government. It applies even to anarchists in the tradition of Proudhon and Kropotkin, who want extremely direct and reconstructed forms of governmental authority. It doesn't apply to libertarian model canvassed earlier, because as discussed that isn't a theory of government proper. It does apply to serious thinkers like Hayek and Nozick during his libertarian phase (they just think authorities like described above should have extremely limited domains), but Ron Paul bears as much resemblance to them as he does to the Emperor of Japan.