Yes, but the parsimonious explanation is that neither Democratic politicians nor Republican politicians nor any other kind of politicians are particularly careful with their facts, and which you think are more prone to "lying" has more to do with the listeners than the speakers. The idea that any politician is routinely dealing in truth is laughable... and I don't mean that so much in terms of cynicism per se, but because they really have very little incentive to do the necessary huge amounts of work it would take that would bring them no gain, or even less than no gain inasmuch as it would limit their verbal weaponry.

Just as one example of the sort of thing that makes it difficult for me to take Politifact ratings seriously in 30 seconds of browsing, look at: http://www.politifact.com/truth-o-meter/statements/2011/sep/... Mitt Romney gets a "pants on fire" rating for claiming that Obama has apologized to the world for the US on various occasions. To my eyes, it's a desperate attempt to avoid the accusation by deliberately and stubbornly being as naive as possible, insisting that it wasn't anything remotely resembling an apology ("pants on fire" remember, not just "half truth", which I would actually accept just fine on this matter) because it doesn't contain the word "sorry" and never quite fully says "apology". I call it "naive" because in politics everybody knows that there's more to what's going on that just what is being said; would Politifact expect me to be naive enough that when diplomats say they had the traditional "frank exchange of views" that means the negotiations are going well, because nobody said outright they were going poorly? Of course Obama never said "I apologize for the US", but there's rather more wiggle room for interpretation than giving someone who says there were an apology a "pants on fire" rating.

And to be perfectly clear, I see equally dubious straining-at-gnats attacks from conservatives on liberals as well routinely. The only way these "truth goggles" could actually work is to draw from a wide variety of sources and hope the bias cancels.