Greek and Roman citizens had the right to vote linked to their duty of military service at times of war. E.g. Athens had lots of free non-citizens who did not have that privilege and that duty. (Also look up the etymology of the word "idiot".)
Democratic institutions in Europe started to crop up (sometimes as a result of revolutions) when subjects to a particular crown started to be drafted, and thus learned military skills. Nobility, who traditionally had some freedoms and could even be elected to various councils and parliaments under a monarch were also usually bound to military service.
People of the US in particular won their right to vote as free citizens (and not be subjects to British crown) in a literal war in 1775-83 (and then again in 1812).
That "price of freedom is eternal vigilance" idea also links these two ideas pretty tightly.
In a civilized society, this force is normally only exerted by specially designated people, the police force, and, more rarely, by citizens defending themselves against assault.
But any society that wants to preserve itself has to have an army, or some other kind of a self-defense force, else the first invader to come by will overrun and subdue it. Delegating this to someone who are not the citizens possible to an only very limited extent.
Violence is not a great thing, sure, but sometimes it's the lesser evil, when the greater evils are serfdom or extermination. What a civilized society has to curb is aggression, which is the source of violence.
This is sad. I don't like wars. A war is only worth it when all other means fail. I only see the point in defensive wars; the 1991 war in the Middle-Eastern desert was that, protecting Kuwait. Later, not so much, to say the least.
> violence first, democracy later
Rather, "independence first, democracy based on that". I don't see how this Middle-Eastern warfare ever helped US independence, or e.g. Iraqi independence. Except maybe it helped a bit Afghani independence, because Taliban long-term would likely be even worse that the total disarray they're having now.
https://www.youtube.com/watch?v=kdrjzE1SE58 (depictions of violence, satire)
For those that don't know, Starship troopers is a scathing satire about how "war makes fascist of us all".
To my puzzlement, some people don't notice how ironic it is, throughout.
(Other than being an authority, presumably. Notwithstanding authorities on violence, such as Heinlein)
Try having a political leader jailing people who don’t do what he tells them to do.
That's not the point that was made, however. The post you replied to connected the military to democracies as protectors of their physical integrity.