Far-right leader Marine Le Pen is refusing to endorse either candidate in France's presidential runoff and says she will cast a blank protest ballot. Le Pen, who came in a strong third place in the first round of voting April 22, told her supporters at a big rally in Paris to "vote according to your conscience" and said, "I will cast a blank ballot," explaining that she could not endorse Nicolas Sarkozy or Socialist challenger Francois Hollande. Polls favor Hollande, but Sarkozy hopes to win over Le Pen's voters for Sunday's runoff. (More Nicolas Sarkozy stories.)