We are to establish the contrary by persistent inculcation of the doctrine of equality of liberty, whereby finally the majority will be made to see in regard to existing forms of invasion what they have already been made to see in regard to its obsolete forms, namely, that they are not seeking equality of liberty at all, but simply the subjection of all others to themselves. Our sense of what constitutes invasion has been acquired by experience. Additional experience is continually sharpening that sense. Though we still draw the line by rule of thumb, we are drawing it more clearly every day. It would be an advantage if we could frame a clear-cut generalization whereby to accelerate our progress. But though we have it not, we still progress.