2012/01/27 Headlines: GOP Candidates Spar over Immigration, Wall Street in Florida Debate; Obama Touts Domestic Drilling in Vegas Speech: U.S. is the "Saudi Arabia" of Natural Gas; Pentagon Boosts Overall Spending Despite Short-Term Cuts; Iraq: 32 Killed in Baghdad Bombing; Iraq Mulls Legal Action over Haditha Massacre; U.S. Threatens to Stop Egyptian Military Aid over Stranded Americans; Syria: 30 Killed in "Terrifying Massacre"; Former Guatemalan Dictator Faces Trial; WSF Meets on "Capitalist Crisis, Social and Environmental Justice"; Rejecting GOP, Senate Hikes Debt Limit; Walker Aides Face New Charges; FBI Seeks App to Monitor Social Media; Twitter Can Block Tweets by Country;$