The economy is the number one issue on voters' minds, and it looks like it's going to remain that way considering the daily barrage of bad news from Wall Street. In other words, John McCain simply cannot duck his head down on the issue and hope it goes away by Election Day - he has to address it.
An ad highlighting this is a good way to start. I believe it will play well (from the McCain campaign's perspective) with undecideds all over the nation.
Hundreds of economists (including Nobel Prize winners Gary Becker, James Buchanan, Robert Mundell, Edward Prescott, and Vernon Smith) have signed letters opposing Barack Obama's economic and tax plans (here, here, and here)...
Running a concurrent series of ads touting McCain's own tax plan and detailing how they would help the average working American would be an even more effective use of the $160 million the campaign and the RNC have on hand for the final push.