Caricature has been called "the ungentlemanly art." I suppose that's true, if you think mocking someone's personality, mannerisms and unfortunate physical traits to score political points is somehow impolite.
Political caricature isn't solely the creation of cartoonists and satirists. We get plenty of help from our targets. After all, it was Paul Ryan who fibbed about his marathon time and Joe Biden who claimed he's known three presidents "intimately." What else was Matt Wuerker supposed to do but contort the distortions?
It's always amused me that various renderings of the same person can be so starkly different, yet still seem to capture something of their essential nature. The same artist can even vary someone's caricature pretty dramatically and it still works, witness the Tom Toles drawings below. (Extra points on his artistic license for the Eddie Munster reference.)
Since political debates are largely theater, with campaigns and commentators keeping an ear tuned not just to policy particulars and swing-state fence-sitters, but also to potential pratfalls and swing-for-the fences "gotcha" moments, they are, in addition to being entertaining, opportunities for candidates to alter the pre-conceived notions. To re-draw their caricatures, if you will.