Exit polls

No, I don’t mean polls of US liberals fleeing the country. But here’s a puzzling thought. There’s much discussion in the US media about the fact that that exit polls (which indicated Kerry was winning) turned out to be wrong. How to explain the discrepancy. Did people leaving polling stations lie to pollsters about how they had voted? Was there something wrong with the sampling methodology of those conducting exit polls? Or was there something, er, wrong with all those polling machines? After all, we knew in advance how flaky they were — and how vulnerable to tampering. I only ask.