Ed O'Keefe

Republican presidential candidate Ted Cruz is close to ensuring that Donald Trump cannot win the GOP nomination on a second ballot at the party's July convention in Cleveland, scooping up scores of delegates who have pledged to vote for him instead of the front-runner if given the chance.

Growing evidence of far-reaching federal surveillance of the phone records and Internet activity of millions of Americans reignited the debate Thursday about how aggressively the federal government uses its surveillance powers to protect against terrorist attacks.