Mitt Romney has the highest disproval ratings of any presidential candidate in the past 36 years. Just what is it about Mitt Romney that turns off Americans?

New York Magazine's Jonathan Chait suspects it's a lingering hangover from the George W. Bush administration.

The Bush years deeply discredited the GOP, and while Republicans were able to make gains in 2010 by default, as the out party during an economic crisis, they did nothing to rehabilitate their image. Indeed, they have embraced even more unpopular positions than the ones that George W. Bush advocated. Romney has taken up the banner of cutting Medicare in order to make room for lower taxes for the rich, and that’s an incredibly unpopular trade-off.

What else? Romney has come to be defined by his wealth to some degree. This is not a problem if you’re able to pass yourself off as a rich guy looking out for the little guy, and Romney has tried to pass himself off this way. But it’s very hard to pull off given his actual policies. Romney has made his shorthand identification “I’m a conservative businessman.” That’s not a great sell for a Republican, except among hard-core Republicans (and, really, affluent Republicans, which is Romney’s base.)

Finally, there may be a way in which the lack of enthusiasm even among his supporters creates a kind of general downdraft. Consider this quote from conservative pundit Fred Barnes, which is intended as a solid endorsement of Romney: “His plan was to run as a moderate but govern (I think) as a conservative. He’s abandoned the moderate mask and positioned himself firmly in the conservative camp.” Barnes means this as a compliment, but the subtext is that Romney is a huge liar. Romney has been forced to reinvent his persona so many times that it has become impossible for almost anybody to buy into the idea that he is a consistent, principled figure.