Tunisian leader Zine El Abadine Ben Ali was in power for 23 years before widespread protests forced him to retire on January 14. Hosni Mubarak was president of Egypt for 30 years before resigning on February 11. And Muammar al-Gaddafi has been in control of Libya for a staggering 42 years, after taking power in a coup. Now, two of them are out of power, and the third is on the ropes. And people with similarly oppressive leaders are standing up to them across the Arab world. The contagious nature of revolutions stems from a sense of shared humanity....