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The question all along has been whether McCain and Clinton are more (or less) unifying, because that's how Obama framed the terms of debate at the outset (that and 'hope' and 'change'). This in itself was an entirely false premise - something more in the nature of a crusade rather than a political campaign meant to deal with concrete issues, but initially at least, Obama got away with it. And that's where all the trouble started.
This looks to me like a knub of interesting things. First off, I wouldn't make overly grandiose claims about Unity or even the need for it. I think Obama himself is looking more for redefinition rather than assimilation with the Borg. A bipartisan consensus, a working majority is not Unity. There's clearly some folks on any side that don't want Unity. In the name of Unity we shouldn't attempt to kill off political diversity. I personally would like to continue to raise my freak flag high and live through my life the way I want to.
Yet, the only reason that Obama was able to frame the terms of the debate around hope and change at the beginning of this election cycle is because those ideas deeply resonated with the public. Obama didn't create this wave, he just showed up in time to surf it. Changing the process is not a false premise, and it is very concrete because people are reacting to how politics has been conducted for nearly eight years.
They are reacting against the political strategy of Karl Rove, his 51% percent strategy that divides the country against itself. It encourages and relies on one half of the population to demonize the other. This strategy was useful for perserving the power of the ruling majority, but not so good at advancing the interests of the American People. At this point in time, the US has some very large challenges on its plate, and a lot of people sense that a 51% buy in is not going to cut it. Nothing is going to get done, nothing is going to change, unless there is sufficient buy in. It doesn't require Unity. A supermajority would probably do.