Arthur, who served after President Garfield was assassinated, may well have possessed the basic qualities of a great leader. But the time of his presidency was fairly stable, so he was never called upon to step up.
Tough times, on the other hand, are when great leaders show their stuff. If you look at many of the famous leaders throughout history, you'll notice they became famous because they navigated through seemingly impossible times. They held the flashlight at the end of the tunnel.
by David Mammano
Full Story: http://blog.inc.com/start-up/2008/10/how_great_leaders_thrive_in_to.html