“A country’s credibility, at least during crises, is driven not by its past behavior but rather by its power and interests. If a country makes threats that it has the power to carry out—and an interest in doing so—those threats will be believed even if the country has bluffed in the past…. Tragically, those countries that have fought wars to build a reputation for resolve have wasted vast sums of money and, much worse, thousands of lives.”