Marco Rubio: "The majority of Americans are conservatives."
PolitiFact: "Mostly true."
Actual fact: A 40 percent plurality of Americans identify as conservative, not a majority. That's not just a temporary thing for this year; Gallup has never found a majority of Americans identifying as conservative.
It was a different story when Ron Paul claimed that "The majority of the American people believe we should have a gold standard and not a paper standard" for currency. Then, actual fact and PolitiFact agreed: a national poll showed that 44 percent of Americans support a gold standard, and 44 percent is not a majority. PolitiFact rated Paul's false statement "false."
So why is it false when Ron Paul claims a majority for a position held by 44 percent of people, but "mostly true" when Marco Rubio claims a majority for a position held by 40 percent of people? PolitiFact's defense of their Rubio PolitiFail is that:
Our goal at PolitiFact is to use the Truth-O-Meter to show the relative accuracy of a political claim. In this case, we rated it Mostly True because we felt that while the number was short of a majority, it was still a plurality. [...] It wasn't quite a majority, but was close.
That's a helpful clarification of what PolitiFact is all about. See, where you might have looked at their name and seen the word "fact" in there and assumed that PolitiFact was about facts, it turns out that they're about "relative accuracy." Accuracy relative to what? Well, that's for PolitiFact to decide on a case-by-case basis, but apparently there's no guarantee that what they're showing is accuracy
relative to the actual facts. They might decide to gauge accuracy relative to how dreamy Marco Rubio is or relative to their fear of looking like biased liberal media if they call Republicans liars as often as Republicans actually lie. Since the Republican establishment doesn't care if you call Ron Paul a liar, "relative accuracy" and actual fact can coincide in his case, even though he was four points closer to accuracy than Rubio.
Sometimes, a claim is worded in a way that there are multiple possible answers to whether it's true. In those cases, it's useful to understand how the claim can be justified or, alternatively, how it can be taken apart. But when a politician says something totally straightforward, something that there's a simple yes or no answer to and PolitiFact refuses to engage it on that level, acknowledging that "It wasn't quite a majority, but was close" but still saying the statement "the majority of Americans are conservatives" is "mostly true," they deal yet another blow to their own already minimal credibility. Which is good, because an organization that operates this way doesn't deserve any credibility.