That is not what has ever happened at any point in time historically, I actually can’t think of a single example. When war is on the doorstep support for your own side typically hardens massively.
The times where populations have turned against wars have always been when the troops are fighting far away from home in lands that the home population feels they shouldn’t be dying in.
This will only make people cling to support for the military because they rely on it for personal safety.