I would imagine that in a "1984 world" at first there would be a half that sees through the lies, but after time those who don't love Big Brother would become extinct.
I always wondered how BB had pulled it all of, but seeing a President who read 1984 and thought it was an instructional manual shows me exactly how it could happen.
Orwell was short on explanations about HOW we'd get to that world, but with liberals, I can see it pretty clearly. 0bongo says X, when the truth is Y. Anyone pointing out that the truth is Y is labeled the worst, most shamefully horrible thing imaginable - a shame so bad that it's unrecoverable. To a liberal, of course, that shame is being called a racist. It just so happens that 0dumbo is black, so the racist label is just credible enough to use.
And there you have it - people willing to believe anything they're told, even when they know it to be a lie - just to avoid a fate much worse than death, in this case being called a racist.