Arlington's Democratic Party has set as it's goal to turn out 80% of the electorate, with 80% voting for Obama (and Mark Warner for Senate). It's the "80 in '08" strategy.
We'd be shocked if they reached that goal, but 70% is not out of the question.
It's really remarkable that Arlington is so Democratic. It's actually not a ragingly liberal place, but it is moderately liberal. In fact, Arlington Democrats epitomize "good government" values. The County's AAA bond rating is practically sacrosanct, and unlike our Democratic neighbor to the north (the District of Columbia) government services in Arlington work pretty well.
It's also remarkable given Arlington's demographics. Unlike many major cities, including D.C., Arlington does not have a particularly large African-American population that would skew it Democratic. (Blacks make up less than 15% of Arlington's population.)
Indeed, Arlington, like just about any other county, has it's own economic/geographic divisions. South Arlington is more ethnically diverse and less affluent (but hardly poor), whereas North Arlington is whiter, very affluent and dominated by single family homes. Yet, in the last couple of elections, not a single precinct in all of Arlington voted for a Republican candidate.
In other words, Arlington is pretty liberal throughout, and whites in Arlington are just about as apt as anyone else to vote Democratic. (You can also tell this by looking at yard signs as you drive through any of Arlington's predominantly white northern neighborhoods.)
We're not sure why this is. Probably a series of related factors. One is that good government ethic: if local Democrats are giving you good government while generally minding the purse strings, it makes you feel a lot better about them. Two is that Arlington is well-served by mass transit, and so attracts more liberal-minded urban whites. Three is that Democrats find a welcoming community, whereas conservatives may be more likely to move further out (say to McLean) to be with their fellow travelers.
Whatever the reason, we do like it. And we hope the locals shock us, with "80 in '08."