This Is the Dawning of the Age of Majority

Declare 'var' variable string() /*default NULL*/

While var in (tax, education, agriculture, currency, road subsidy, law enforcement, drug, intellectual property,  energy, occupational safety, environmental protection, wage, housing, fishery management, near-earth object monitoring, climate, seismic event protection, medical, banking, monetary, fiscal, common law, et al)

begin
What is the ideal [var] policy zone?
end

Each one of the items in my variable list above is the object of state provision or regulation. I am confident that any of my readers could easily add to the list. What I find curious is in matters of scale. I think there's a good case to be made that corrective action should match the scale of the problem. Maybe I have an odd sense of justice, but I find it inappropriate to punish the whole class when one kid sticks his chewing gum under the desk or when the police attempt to seize a motel because they suspect that marijuana was sold on the premises at some point. Similarly, it strikes me as erroneous that existential threats like (catastrophic) meteorite strikes or super-volcanoes are completely ignored by international orgs like the UN.

How about the age of majority? Different ages of majority exist even within the same policy zone. In the US, citizens [men] can be conscripted for military service at age 18, tried for violent offenses in grown-up court as young as 10 (in Kansas and Vermont), can't legally purchase alcohol until 21, must generally remain in school until 16, and can't operate a motor vehicle on public roads under the age of 15 (there seems to be no statutory age restrictions on airplane pilot licenses in the US). The American political process still seems to be willing to grant at least a little discretion to smaller organizations on the details of raising children (compared to some European countries, anyway). Are these different standards evidence that the "age of majority", such as it is, has partitionable optimal policy zones? Do political elites understand that there might be some variation in kids' ability to estimate the euvoluntarity of particular types of transactions? If so, why do they seem unwilling to grant that there might be variation in learning ability or educational desire? I can't recall major party political commentary on education in the past quarter century that didn't bemoan relative STEM performance or talk about "standards", as if education were comparable to the missile gap charts used to scare Americans at the height of the Cold War. It's almost as if nations' relative rankings in educational performance was some sort of bizarre international contest.

What is the ideal age of majority policy zone? Given that there's not a lot about being a child that could be considered euvoluntary, how much individual sovereignty should children retain? How much sovereignty should parents retain? Extended families? Voluntary associations? Local districts? Why has the median voter consistently answered "less" on each of these over the past couple decades? Why is Franklin K. Beltway now assumed to know what's better for Jimmy F. Cornhusker than his parents are? What's changed? Has being a kid suddenly become less euvoluntary than it was before NCLB was signed?