Ad hominem may stand as the most commonly used logical fallacy. Instead of judging an idea on its merits, ad hominem focuses on the person expressing it. We see it all the time in politics.
Take a policy proposal like National Popular Vote. There are certainly valid arguments against the proposed state compact to award the presidency to whichever candidate wins the popular vote. However, the fact that George Soros supports the compact is not among them. It’s either a good idea or a bad idea, regardless of where it came from.
Yet, for whatever reason, likely because it proves simpler than thinking critically, many people tend to base their judgments on association rather than substance. The trend bears out in a recent poll from The Huffington Post (you’ll excuse the source, hopefully):
How much can namedropping a politician matter? Conveniently, Republican front-runner Donald Trump shares a couple of policy positions with Obama and other leading Democrats. In a new HuffPost/YouGov poll, we randomly assigned one half of the 1,000 Americans surveyed to say whether they agreed with positions Trump held. The rest were asked whether they agreed with positions held by Obama, Secretary of State John Kerry or current Democratic presidential candidate Hillary Clinton. The trick: the positions were actually the same.
Yet respondents’ reactions were decidedly different. Hearing that Trump supported a certain policy was enough to cause Democrats to reconsider ideas they’d otherwise support, and for Republicans to endorse positions they’d usually avoid.
Perhaps we’d be better off if we considered policy positions independent of who held them. Of course, that would require thoughtful evaluation.