Has any American president changed his position on major issues this often and then lied about it so blatantly?

I know Europeans have to be careful when making comments about US presidents. About ten years' ago, an American friend sent me an email in which he denounced George W. Bush in the most intemperate terms: he was a liar, a warmonger, a racist and a draft-dodger who hated the poor and was only interested in feathering the nests of his rich friends. My friend ended by contrasting Bush's sorry record with that of Bill Clinton's glorious reign. I responded by pointing out that this was really none of my business, but that, were I an American, I'd undoubtedly vote Republican and that I'd always viewed Bill Clinton as a slimy, philandering, shape-shifting sleaze-bucket. This didn't go down well: first, I really had to understand that Bush was evil incarnate; second, how dare I, a foreigner, criticise the President of the United States  - after all, my friend would never dream of criticising the Queen! 

I thought about explaining the subtle differences between the British and American political systems, and I considered asking whether he'd have raised the same objections had I slagged off Dubya - but decided to leave it there. We went on corresponding, but kept away from politics thereafter. But now, whenever I post anything about US politics, I feel a bit naughty. I only have three excuses: (1) this is a personal blog which I dont publicise in any way and which nobody has to read if they don't want to - I'm not forcing my views on anyone, (2) American politics have fascinated me ever since a TV journalist friend of the family took me on a tour of the BBC Scotland newsroom in the middle of the Cuban missile crisis (I must have been nine at the time), and (3) what the US President gets up to affects all of us: even if the current incumbent is a dwarf in giant's clothing, he's still without question the single most powerful human being on the planet. 

While enjoying Dan Joseph's video compilation, I began to wonder whether Obama is in fact uniquely duplicitous - or whether American presidents have always changed tack with such abandon and then attempted to rewrite their personal histories so brazenly. After all, no politician in the world faces greater scrutiny than dear old POTUS, whoever that happens to be. But has the internet increased that scrutiny to such an extent that anyone doing the job would end up looking bad? After all, their shifts in policy, their peccadilloes, their failures are endlessly recorded and constantly available at the press of a button: we no longer have to rely entirely on mainstream political journalists to provide a narractive. This is fortunate, given the shameful failure of America's overwhelmingly liberal MSM to hold Obama to account. Or perhaps it's the sense of being constantly under attack from new media upstarts that has caused America's MSM to finally abandon all pretence of even-handedness and to circle the wagons and become shameless shills for the present occupant of the White House. Whatever, thank God for the likes of Dan Joseph (who mainly works for the right-wing site, MRCTV) and Andrew Klavan (of PJ Media and The Revolting Truth) - when traditional media journalists neglect their duties, someone has to fill the void. (Let's face it, if I had to rely on the BBC for my information about US politics, I'd be as ignorant as most Brits were about events in the Soviet Union in the 1930s.)

Speaking of digital media, it can't be a coincidence that the United States and Britain - where the electorates aren't quite as ruthlessly excluded from the political process as in most other parts of the world (especially the EU) - have both seen the rise of influential, populist, anti-Big Government political movements in the Tea Party and UKIP during the period when the internet took centre stage.