How is this a bad thing? There should be a nonpartisan committee that evaluates each political ad BEFORE it hits the airwaves.
Slippery slope arguments aside, how do you go about choosing a level of strictness which is unlikely to
immediately result in problematic suppression of speech while still doing what you're wanting it to do?
Fringe falsehoods are not really a problem, after all. "Obama is a reptilian" is something that'd be really easy to identify as crazy and wrong but which is also basically harmless. Suppressing it is unlikely to do much good, and would probably make things marginally worse because it looks at least a little like a cover-up.
Very few outright
lies even make it into political ads. There aren't any "Obama said he wants to kill all the Christians" ads out there. The sort of dishonesty common in ads is interpretive or implied. If a bill might plausibly increase the number of abortions, even if it's aimed at something very different, is it a "pro-abortion bill"? Ads commonly speculate as to what politicians are
really thinking or planning, and sometimes this is ridiculous, but there's no clear fact of the matter to check the ads against.
I don't think the core idea is
crazy, but at the very least it's the sort of thing that (at least) the major parties would need to buy in to
before any of them go off the deep end. That, right now, liberals think conservative talking points are deeply dishonest, and vice versa, means that you
can't come up with non-partisan rules for honesty in politics. Even if we stipulate that liberals are right and conservatives are wrong, if the facts are partisan then the facts are partisan, and when your political opponents get to influence the fact-finding committee they can be expected to use it against the facts.