Ted Cruz is the toughest guy in the US Senate. Definitely presidential material IMHO.
Here he nails a very evasive Eric Holder over the constitutional permissibility of using drones to kill US citizens on American soil.
This is the interchange that got Rand Paul filibustering. For a quick synopsis, “Cruz Goes After Holder About Constitutionality Of Using Drones To Target Americans On US Soil.” CBS DC.
And about the prohibitive evils of John Brennan: “National Security Experts Warn: Reject Brennan!”
And here is the Obama interview that brought this matter to the forefront, with Barack Obama stating that there would have to be a policy for drone strikes within the United States on Citizens. “The rules outside the United States are going to be different than the rules inside the United States.”