If the most ambitious, colossal prevent defense in modern history — France’s 280-mile Maginot Line built in the 1930s to prevent German invasion — proved a colossal failure, what makes football coaches of both kinds believe they can succeed? Prevent defenses are both footballs’ version of institutionalized insanity, or insanity that should be institutionalized. Just as in 1968 when “Harvard Beats Yale, 29-29,” the U.S. National Team World Cup opener Monday gave us “Wales Beats U.S., 1-1.” The U.S. side, playing with unexpected verve and offensive dominance, had this game won — in the bag — if only it had...