Romney would take a hard line against Cuba and the Castro brothers and reinstate the travel and remittance restrictions that were eased by President Obama. He supports the embargo and has said he would "use every resource we have, short of invasion and military action, to make sure that when Fidel Castro finally leaves this planet, that we are able to help the people of Cuba enjoy freedom."
Overall President Obama has taken a less-hawkish stance on the Castro regime than the Bush administration but he favors maintaining the embargo and keeping Cuba out of the Organization of American states until they adopt free and fair elections. Through the easing of travel and remittances restrictions President Obama has tried to show Cuba that he is open to a new relationship. "If we see positive movement we will respond in a positive way," he said in 2010.
Brazil is the world's sixth largest economy, a member of the G-20 and an important emerging market leader. I was thinking about leaving this section blank because neither candidate ever mentions the country on the campaign trail. The Romney campaign's issue page on Latin America does not even mention Brazil and the Obama administration has done little to advance gains made during the Bush administration.
While there would be some slight policy differences under a President Romney there are no overt signs that he would alter policy significantly or suddenly increase engagement with the region. Alternatively, it is unlikely that President Obama would pay more attention during his second term either. That is a shame. Both the U.S. and Latin America would gain a lot from a President who properly understood the value and benefits of better relations with Latin America.