Ron Paul and Mitt Romney hit former Pennsylvania senator in CNN debate in Arizona
Senate official says letters contained white powder, which was tested and found to be harmless; Stewart, Colbert received letters issuing threats
Activists report regime shelling of Homs continues as helicopter gunships strafe rebel bases elsewhere Colleague pays tribute
Former University of Virginia lacrosse player faces up to 40 years in prison in slaying of girlfriend; Jury deliberated for nine hours
Police used large canister of spray on students involved in seated, non-violent "Occupy" protest; Video went viral on YouTube
Video shows the explosive impact of a train crash in Argentina that killed 49; Passengers claim brakes were bad
In a debate Wednesday night, the Republican candidates lamented government intervention in religious issues and the breakdown of the American family
Third-grader shot in the abdomen at an elementary school in Washington state; One of her classmates was detained
Pakistani official says 17 workers fired for taking part in CIA's fake vaccination program meant to get bin Laden DNA
Amine El Khalifi, charged with plotting a bombing in the Capitol, waived his rights to preliminary and detention hearings