We've just had a weird run lately. Obama was your traditional politician. He had no compunction about a bald-faced lie ("if you like your plan, you can keep your plan"; "we're going to lower the average cost of healthcare by $2,500"; "Benghazi was caused by a film maker", etc etc), but he still mostly acted like he was constrained by trying to maintaining some credibility. He might have lied more boldly because he knew the press would back him up, but he still more or less pretended that he generally told the truth and the people he was talking to would have a memory longer than a goldfish's. Then there's Biden, who says whatever he thinks is most politically advantageous for the next 5 minutes. No concern about relation to the truth, but you basically knew every time what his motivation was for saying whatever he was saying. Then there's Trump, who what he says has nothing to do with the truth, but is whatever he thinks is maximally advantageous for whatever deal he is aiming for, but you don't necessarily know what deal he is aiming for, and unlike Biden he sometimes has goals that extend beyond the current news cycle, although that doesn't mean he won't say two completely contradictory things within 24 hours if what is best for his "deal" changes in that 24 hours. Just zero value put on credibility, which is just 180 degrees from the way most people negotiating deals treat it.