Actually, libel is an interesting thing. The truth, of course, is an absolute defense. But to prove libel, you have to prove that the person either knew that his comments were false or "recklessly" failed to investigate the facts. See NY Times v. Sullivan 376 U.S. 254 (1964) which applied the term "actual malice" (although the comment need not be an intentional lie). However, as in every civil case, the plaintiff must not only prove conduct but must also prove actual injury. Kanye's "Bush hates black people", for example, could be slander if Kanye knew it was untrue or "recklessly" failed to investigate whether or not it was true. BUT it would only be actionable if Bush could prove that he was suffered monetary harm.

An interesting result is that comments that are so outrageous that no reasonable person could believe them, there is legally no libel. So your example of an accusation that Obama is a convicted pedophile unfit for office would very likely NOT be considered libel because Obama would not suffer harm to his reputation as the claim is so outrageous that no reasonable person would believe it. This is precisely what happened in Hustler Magazine v. Jerry Falwell. Falwell sued Hustler and Larry Flynt over a satirical "interview" in which Falwell admitted to being drunk and having sex with animals and his mother. The interview was so obviously false that Falwell could not have been injured because noone would have believed the story.

Here, Saule's ridiculous comment about Pres. Obama "going after our children" is limited to eha viewers, none of whom take Saule serious on any issue, let alone a commment like this. Saule need not fear being sued for libel.