For some time now, American politics looks like it is being conducted by two opposing factions.
Nothing new there - two-party politics have been the norm in the USA pretty much since party politics began there, just as they have in British politics (except for brief periods here, one of which is current, where a third party commands wide support).
However, in the past in the US, and for most of the last 20 years here, the key to political dominance by one party or the other was to gain the support of the political middle - ordinary voters who are neither right or left-leaning. My perception is that this way what won Clinton his two terms - the left didn't get it's own way, but had to compromise and negotiate.
Tony Blair's electoral success, like the Thatcher/Major government before him, was founded on his ability to frame the debate around issues that were important to the political middle. His grip on this is pretty secure - so much so that losses of support from the left, over Iraq, for example, haven't greatly damaged him. (Much less than some of us on the left might have hoped, anyway

).
And the new Tory leader announced yesterday, David Cameron, has pretty much announced his intention to battle squarely for this centre ground, reversing the strategy of being rightwing that has lost his party the last three elections.
However, the Bush administration in particular seems to have relied on mobilising the hard right (though not the far right to my knowledge) and pretty much ignoring the middle and the left, at least in their public pronouncements.
One side effect of this seems to have been a polarisation of the electorate, and certainly a polarisation of the media - very little
commentary seems to come from the middle these days.
Increasingly, it seems that the moderate left and moderate right are being driven apart; that the core assumptions being made on either side are so diametrcially opposite that its next to impossible to have a conversation about a particular issue, especially today's hot topics like abortion, gay marriage, Iraq, etc. The political centre ground appears to be completely empty, or to have just vanished.
Example - here on

this week, we've had a thread from the right that talks about whether criticism of the conduct of the Iraq War constitutes treason, and another from the left that assumes (I'm paraphrasing) the Bush administration lied over Iraq and asks (at the time of writing, in a way that breaches

rules) whether the motivation for those lies was malice or stupidity.
Is the political middle ground being ignored by politicians and/or the media? Why?
Has it disappeared altogether? How and why?
What are the consquences of the current polarisation? Do compromise and negotiation even matter?
How can the right and left talk to one another when they seem unable to agree on anything, including the parameters for debate?