That’s going to lead to war, not peace.
The way moral hazard works is the guarantor of peace ends up bearing most of the costs, because the nations whose security is being guaranteed, weaken themselves to the point that their defenses are weaker than they would be, even with the guarantor's forces, if no alliance existed. And in so doing, they tempt an aggressor to invade, on the assumption that the guarantor will balk at the high costs of carrying allied deadweight. If there's going to be war anyway, why not let the nations directly affected fight it and bear most of those costs?