Want to be one of the greatest leaders of all time, with a wealth of success, power and respect? Try doing nothing for a change, says Harvard historian Nancy Koehn. This counterintuitive advice applies to moments of crisis, when the stakes are high and emotions are tense, because that is the very time when you're apt to make errors in your decision-making. Anger brings weakness, but you can conquer the trap of emotion by removing yourself from the situation, and sitting in silence to think. To prove that doing nothing in times of severe anger is a leadership skill worth developing, Koehn tells the story of the most important letter Abraham Lincoln never sent—if he had had email or twitter (i.e. quick reactions) back in 1863, the outcome of the Civil War and U.S. history may have been drastically different. It turns out you can win almost any fight if you learn how to respond thoughtfully in time, instead of reacting rashly in an instant. Nancy Koehn is the author of Forged in Crisis: The Power of Courageous Leadership in Turbulent Times .