&lt;p&gt;The Mexican presidential candidate for the Institutional Revolutionary Party (PRI), Enrique Pena Nieto speaks during a meeting with the international press in Mexico City. Pena Nieto delivered a stunning return to power for Mexico&#39;s once-reviled PRI party, but the president-elect faces a stiff challenge in cutting poverty and clamping down on rampant drug violence.&lt;/p&gt;