I’m all for that but national ads reach swing state voters too. Sometimes the national sentiment spills over and helps in states you never expect. I think Obama’s rise in the polls are directly tied to his onslaught of national tv ads. If most of America doesn’t get Romney’s message, they are left only with the lies and deceit of the left. Most Americans are not politically active and get their news/views from dubious sources.
You seem to think that every ad that you see on a program plays all over the country. That is not true.
It is possible that in the very slot you see an Obama ad, someone in another location sees a Romney ad. I live in Alabama but in the Mobile/Pensacola tv market and I have not noticed a lot of ads for either candidate. Then again I do not watch much tv other than sports and certain cable shows.