What constitutes written malice? how does one cross the line between insulting a public figure you don't like and writing something that constitutes "malice"?
The term "actual malice" has a particular meaning under defamation law and should not be confused with the more generic notion of ill will that occurs in other wrongs.
Actual malice is a defamer's mental state at the time of spreading his defamatory falsehoods. That mental state is the defamer's knowledge that his statements were/are false or, in the alternative, the defamer's reckless disregard of the truth or falsity of those statements.
That being said, the actionability of a false statement for its falsehood depends on (1) the extent to which the statement could reasonably constitute a statement of fact that actually took place, and (2) the realistic possibility that the statement of fact injures (or tends to injure, in the case of defamation per se) someone's good name and reputation under others' belief that the event(s) at issue took place.
Thus, item (1) rules out the actionability of hyperbole, and and (2) rules out the actionability of statements of opinion even if that opinion convinces others to dissociate from the would-be plaintiff.
The actionability of the cartoon you hypothesize depends on how exactly the president is made "look grossly evil". For instance, if the president is portrayed as committing sexual abuse, the cartoon is defamatory per se, regardless of how many fingers other characters in the cartoon have.
By contrast, making the president "look grossly evil" by picturing him with a smile 'a la Mr. Burns', even with horns, is hardly cognizable as defamatory. It simply cannot be said that the cartoon falsely imputed or attributed to the person some misconduct or despicable act.
Likewise, being a cartoon and one of the characters therein having six fingers weakens any presumption that an event took place where the president and "a product of genetic engineering" got together to conspire.
Of course, if it can be proved that the president truly met with lobbyists/others for illicit purposes, that proof would strike any legal merits the president would have as to being defamed by the cartoon.
Regarding the caption, the prefix "I'll bet" conveys more the publisher's guess or subjective belief than a narrative of facts that allegedly took place. Other than the prefix, the caption itself seems inconclusive, whence ascertaining the defamatory nature thereof would require assessment of the context in that publication.
A real life example of non-actionable cartoon is at the end of this post. Several items in the cartoon render it non-defamatory:
- It clearly is hyperbole that judge Carol Kuhnke has a pet whose head is thrice bigger than hers, or that the dog is articulate enough to speak as portrayed in the cartoon. This is somewhat an analogy of the six-finger character in the cartoon you hypothesized.
- The prescription drugs mentioned by the dog are listed in the police report that ensued when this judge was busted for illegal possession of drugs. A relevant excerpt of that report is posted just prior to the cartoon, thereby preempting the notion that the cartoon dog was just "making up" names of prescription drugs.
- The furniture next to which the judge is sitting symbolizes the tool chest in which she stashed the illegal drugs (together with the legal ones). Since the tool chest is (or was) located in the judge's home and possession --without the requisite prescription-- of drugs is a felony in her jurisdiction, this judge's home qualifies as crime scene.
- The label of "joyful judge" is a truthful and satirical reference of her expressions of joy that you will see in the first image of the post.
With these and other elements of truth, hyperbole, and satire in the post, a public figure like this judge would have a hard time proving that the cartoon is false, let alone that it was published with actual malice. Any allegations that the post was published "with knowledge of falsity or reckless disregard thereof" is stricken by the number of details taken from the police report which she did not dispute even when the prosecutor asked her to recuse from two cases back then.