> Which begs the question on how one collects taxes without aggression?
That is what the Rothbardians do not understand -- there is always aggression in the world. What you do not understand is that even though there is aggression in the world (i.e. we don't live in a perfect world where people don't game the system), that does not mean we should not seek to minimize it. To minimize aggression (and thereby maximize freedom) is a non-trivial and ever-changing optimization exercise.
For example, if by levying a tariff or property tax, a freedom-maximizing society's government is able to fund a standing army to prevent other governments from conquering a society, it is presumed that net aggression is minimized (i.e., from the standpoint of the citizenry who are being aggressed upon by their government in the form on involuntary taxes, because otherwise we can assume a different government would take its place, which would most likely not be a freedom maximizing government (or it wouldn't have been forming empires in the first place)).
> So you criminalize the "assault" then you don't need gov't watchdogs tracking all uses of mercury to ensure it doesn't end up on some poor sap's lawn because once you give them the power to outlaw one thing you give them the power to outlaw whatever they want.
Not sure what you're getting at here, if anything. I see no connection between 'lack of government watchdog employing mass surveillance to track all thermometers in the country' and society falling apart. Nor do I see the converse as an actual solution to mercury pollution -- do you?? So they track it, then what? How? What happens when thrown-out thermometers break and run off into the storm drain? What happens when somebody throws out mercury on some poor sap's lawn anyway? This is the second time you've made this invalid point -- people will break the law sometimes. There is punishment for that in both of these proposed systems. How is yours any more effective?
There will always be littering, and I whole-heartedly support generic clean-up efforts to counteract the summation of small, non-enforceable aggressions, that are not already assumed in externality taxes along the supply chain (like people dropping gum on the sidewalk, etc.) On the topic of those externality taxes, here's an example: purchaser of a combustible manufacturing fuel used to create cigarettes is charged an externality tax for the inherent environmental cost of using the fuel. Then the smoker pays a different tax to pay for the externality inherent in using the cigarette. Such a thing would not be fair for gum, though, because most people do not drop gum on the ground -- it isn't inherent so why should the Sean Spicer's of the world bear an outsized burden of the cost for cleanup?