Somewhat like the reverse of the Swiss, where everyone is in and the state issues the weapons.
Now it seems self-evident to me (although it appears never to have been done) that the militia was intended to be there for the government to call upon in times of national emergency - a sort of backup emergency army for a state that never really wanted a standing military force.
Yes, but which government? The contemporary reference to ‘State’ is to the individual states of the confederation of states which then comprised the United States. Hence the state governors having primary control of the militias. The standing army issue goes back to Charles I and then to Cromwell, and the fear of a standing army being able to usurp parliament and instal a dictator. The concerns about a standing army are rather ironic, considering the size of America’s standing army, navy and air force since WWII. And even more ironic in Britain, where Cromwell’s Model Army generated the original concern.
Hence, from this you can conclude that the state has the right to call upon the militia for some form of service in the event of an emergency, when this service is critical to the “security of a free state”.
Which has its origins in the English, and other, systems of citizens providing military force going back to the fuedal obligations in the Middle Ages.
The problem with old and rigid constitutions is that they can be, indeed have to be, interpreted centuries later to deal with circumstances which were never in the mind of the constitution’s authors. We have that problem with our written constitution, barely 110 years old, based in part upon the American one with the individual liberty bits left out, which sought to deal with a range of contemporary but now largely non-existent states’ rights and states’ fear of the national government issues, among other things, that are totally irrelevant now, but which are still fertile sources for complex constitutional cases that make your brain hurt to read.
Britain avoids these American and Australian difficulties by not having states and by having an unwritten constitution, although it has a written constitution of sorts going back to Magna Carta with subsequent additions flowing from later events, like the consequences of the Star Chamber, which became part of the law and national tradition.
Britain is, compared the American constitution, vulnerable to the state taking away freedoms because it doesn’t have a complete written constitution, as is Australia with no civil rights enshrined in its constitution. Conversely, the absence of a single document allows Britain to respond more flexibly to changed circumstances, admittedly under the impetus of courageous, or adventurous, judges like Lord Denning around the middle of the 20th century. I’m not sure that America could have responded to, say, something like the IRA bombings in England without getting tangled up in civil liberties challenges.
Australia is, so far as personal freedoms are concerned, not much different to Britain, but both disadvantaged by yet happily free of the EU constraints imposed from outside.
