The president's decision not to prosecute CIA agents for torture is being criticized by right advocates.
A documentary critical of the North, filmed by a family member of one of the journalists, could complicate their case.
Summit of the Americas gathers the 34 democratically governed countries of the Western Hemisphere. But communist Cuba threatens to steal some of the spotlight.
Obama releases four secret memos detailing detainee treatment under Bush. Human rights groups slam his promise not to prosecute intelligence officials.
Protests against Washington spending took place in more than 700 US cities Wednesday.
He's likely to stress shared responsibility for rising border violence during trip that begins Thursday.
Economic blame, Cuba, and Chávez, challenge new US-Latin American relations.