Good question. The only reasons I can think of are: 1) Maybe the DNC gets some kind of a discounted advertising rate on national ads that run everywhere in America and fill up empty advertising time that hasn’t already been sold, or 2) as someone else mentioned, the Obama campaign knows that Romney has a solid lead and they’re trying to limit the size of Romney’s victory in the national popular vote, to limit how much political capital Romney acquires from his victory. If it isn’t for one of those reasons, then it’s beyond me why they’re advertising in solid blue regions.
Expensive tv ads in NY, Seattle, Gay Frisco area and ?.
Another reason, we don’t want liberals spending our tax money.
They can’t make good money decisions even with their own money.
Of course we have not figured in matching government funds.