BRASILIA (AFP) - US President George W. Bush ramped up his efforts to curb Venezuela and Cuba's clout in Latin America, accusing them of trying to "roll back" fragile democratic and free-market gains in the region. Amid concerns in Washington that poverty may enhance the appeal of anti-US, economically populist messages, Bush said in a speech that "ensuring social justice for the Americas requires choosing between two competing visions." "One offers a vision of hope. It is founded on representative government, integration into the world community, and a faith in the transformative power of freedom," he told student, diplomats and...