We should bring a lesser calamity upon ourselves by abolishing our quarantine system against the importation of deadly disease and inviting a visitation like the great London Plague, or by letting in the Black Death to sweep our country as it swept Europe in the Middle Ages, than by neglecting our quarantine against war, as we are neglecting it, thereby inviting the pestilence of invasion. Self-preservation is the first law of Nature, and this law applies to nations exactly as it applies to individuals.