Based on PolitiFact’s content I have no doubt PolitiFact, as a whole, leans left. PolitiFact’s funding sources contribute to that picture, but only in a minor way. If BikerSailorDude got $1,000 from George Soros or $1,000 from Charles Koch before writing his article, it isn’t the source of the money we should use to figure out his agenda. The agenda is spelled out in the content.
So it is with PolitiFact. We see the bias with PolitiFact by its inconsistent application of standards. Two related examples help illustrate: PolitiFact rated it “True” that slaves built the capitol building. PolitiFact also rated it “True” that slaves built the White House. Both claims came from Democrats. In both cases, the fact check admitted it was unknown what percentage of the work was done by slaves. So maybe half the work was done by slaves. Or more than half. Or far less than half. But a statement that slaves built the buildings rated an unqualified “True,” as though the free blacks and European immigrant masons who also helped construct the buildings either were slaves or did not participate in the construction.
Missing context like that typically drops a “True” claim down to “Mostly True” or worse.
If PolitiFact could avoid such inconsistency its sources of funding wouldn’t matter.
On the matter of PolitiFact’s funding, it’s also worth mentioning that PolitiFact generates ad revenue for the Tampa Bay Times. The desire to generate clicks from (predominantly liberal) readers plausibly helps guide story selection.