Not only has former Cuban President Fidel Castro resigned the top job, he announced in his latest column for state-run media that he has stepped down from the Communist Party's central committee, too. It’s time for younger leaders to step up, Castro says. “There is no margin for error in this moment in human history,” he wrote. “The new generation is being called upon to rectify and change without hesitation everything that should be rectified and changed.” An ailing Castro, who led the Communists to power in a 1959 coup, surrendered the presidency to his brother Raul in 2008, although Raul Castro had been acting as president since 2006. Raul recently announced a set of government reforms, including term limits for officeholders.