stAllio has a nice run-down of the confusion surrounding John McCain's houses. And, in fairness, it is complicated. As Yglesias hilariously puts it, "When one of your homes is really a combination of two different luxury condos the metaphysical status of your property comes into question. You'd really need to ask a trained professional mereologist to resolve the issue and can't expect McCain to speak to it personally."
In all seriousness, this is the sort of political attack that I find, on the merits, sort of silly, but that is, nevertheless, often devastating. There is a temptation to be high-minded here. John McCain's money is mostly his wife's and I assume acquired most of the properties and he has had precious little to do with their maintenance, so I'm not surprised he doesn't have a clear idea of how many houses he and his very wealthy wife own. The relevant issue is that his policies will disproportionately benefit very wealthy people like himself at the expense of most other Americans.
But high-mindedness won't feed the workers and I'm pleased to see the Obama camp giving McCain a solid dose of their own medicine. After the utterly asinine attacks they've been circulating so far -- celebrities and air gauges and all -- I have no sympathy for their plight.
[Edited to add]
I'd note that this attack will be particularly devastating precisely because it does a great job of summarizing a number of different attack lines. Images of John Kerry wind-surfing were perfect Republican fodder because they combined attacks on Kerry as a flip-flopper (textual use) and as an effete elitist (subtextual use). Similarly, the McCain's Houses approach combines (a) textually, John McCain is wealthy and represents the interests of wealthy people at the expense of the interests of poor people with (b) implicitly, John McCain is confused and doesn't really seem to know what's going on. The former nicely capitalizes on Obama's economic issues edge -- which has been eroding slightly but is still quite clear -- while the latter begins to neutralize McCain's primary asset -- his "experience". Of course, I should also add, while it's a smart move to play offense on this, credit is due to McCain for making this fairly obvious gaffe in the first place. Obama's people would have to be idiots not to push on it.