History tells us over and over that freedom is never free, that it must be fought for, maintained and renewed ever and again, in all the circumstances that a particular epoch requires. Lulled half to sleep by two oceans, the abundance of our lands, the enduring vision of our Founders, and the sacrifices of our forebears, we came to think of our country as impervious to ruin, a citadel of freedom and prosperity that would always fend off invaders from without and nefarious forces from within. That no matter our external challenges or inner turmoil, we would, in the end,…