If you want insgith in to the legallity there are plenty of resources. Here’s one:
eff.org/issues/bloggers/legal/liability/defamation
It does not seem that true belief is a sufficient defense.
It is my understand that there are differences among jurisdictions.
In my state, the elements of libel are:
-publication (basically, “spreading it around widely”)
-of a defamatory statement (something a reasonable person would consider inherently negative as that person’s character or actions)
-that identifies the plaintiff.
-That is false
-That is published through the requisite degree of fault.
-And that damages the plaintiff’s reputation.
-And is not privileged.
Now, someone on CAF questioning where Obama was born meets few of the criteria.
-Doubtful “publication” since it’s a limited audience with no particular reason to think it would go further.
-Doubtfully “defamatory”. There is nothing inherently negative about saying a person wasn’t born in the U.S. or might not have been. “Birtherism” is simply questioning a candidate’s legal qualifications for office.
-That is false. I think we can stipulate that the “birther” assertions were false.
-The “requisite degree of fault” is plain negligence, that is, taking no effort to ascertain the truth of the matter. Alternately it can be “libel per se” requiring “malice” (that is, knowing its false but saying it anyway.)
-Doubtfully damaging to Obama, as it probably changed few or no votes.
-Almost certainly privileged. People who are intentionally public figures are generally “fair game” in any controverted, and particularly political, matter. That’s why most of the falsehoods asserted in the media against Trump (or on CAF for that matter) are not “libel”, legally. Holding political discourse to absolute certitudes is deemed violative of the right of free speech in the U.S.