CARACAS, VENEZUELA - Maria Corina Machado doesn't hesitate when asked her feelings about the possibility of going to prison for up to 28 years for "treason to the nation" and conspiracy. "I'm scared, I'm very scared; I have three kids," the political activist says softly, sitting in her small office in the Caracas headquarters of Sumate, the organization that led last year's unsuccessful bid to recall President Hugo Chávez from office. Mr. Chávez's landslide victory in that vote only added to the troubles of Ms. Machado, Sumate's vice president and the woman who has come to symbolize the anti-Chávez opposition....