> When Jimmy Carter says the media is applying a different standard to Trump, it lends credibility to the idea that they just might be.

Not really. Carter is a qualified expert in some things, but analyzing media bias is emphatically not one of them. Now, as a statement that seems at odds with Carter's assumed partisan bias, him saying it may be more credible as a genuine statement of belief than of a source said the same thing with either no obvious partisan bias or consistent with obvious partisan bias, but that's not the same as lending credibility to the claim itself.