There would be no war pretty soon.
Something similar has been suggested for starting nuclear war: if things are bad enough that you are willing to doom whole populations of mostly-innocents to their death, you shouldn't have any trouble directly killing one more.
You could make it even more symbolic by doing it as seppuku instead: if you have failed badly enough as a politician that politics isn't even an option anymore and many soldiers have to pay the ultimate price to make up for your failure, then you should be the first one to do so.
Sadly, they care less about their own children usually than if you made it far simpler, simply make the full cost of any war totally and solely payable by the ruling/upper classes through both immense taxation on their income, i.e., 90% and a wealth tax of 10%, total forfeiture of all assets if they is any attempt to hidden them and are not reported, and a bounty of 50% for discovery of any unreported assets.
Now THAT would end all wars everywhere, except it would likely also cause the money to try to escape to a place that does not have such policies and use that as a base of operations to build/raise a force of subversion, infiltration, corruption, etc.
Frankly, people really have very little understanding of the "shape" of what they are up against. It's often dismissed and I don't even think the people who call it "spiritual warfare" really understand it either, but it is essentially a power, a force that has been often described, but never defined or identified properly that is essentially an abstraction, a graph, more an amorphous fluid dynamic than a material thing. If you know anyone that is an extremely manipulative narcissist and pathological and deliberate, psychopathic liar, you have come face to face with the constantly shifting, ducking, weaving, and orchestrating nature of the system that so many are hard pressed to understand because it is not a line of men on a battlefield, it is not a missile, it is not even "money" it is data, digital transactions of "currency", information as currency... the life blood of manipulation, abuse, and evil.
Needing to use a draft is a bad sign - the more of your soldiers are volunteers the better quality you'll get out of that.
That's a luxury position, which unfortunately not every country is in.