John McCain’s campaign continues to focus on the economic turmoil of the last two days in its latest ad, “Foundation”:

You, the American workers, are the best in the world. But your economic security has been put at risk by the greed of Wall Street. That’s unacceptable.

My opponent’s only solutions are talk and taxes.

I’ll reform Wall Street and fix Washington. I’ve taken on tougher guys than this before.

Two aspects of this ad make it intriguing. First, McCain simply talks into the camera, and except for a couple of shots of the New York Stock Exchange, Barack Obama, and Joe Biden, that’s the visual focus of the commercial. It’s a change of style that emphasizes the “straight talk” theme and attempts to make a personal connection to the voters watching it.

The second is the optimism that McCain uses in this ad. He obviously hopes to contrast his approach to that of Barack Obama, who’s been stressing doom and gloom — the better to sell the need for wholesale change, although with the Bush administration nationalizing AIG, Obama may not be much of a change at all. Instead of offering fear and loathing, McCain exudes calm and confidence, and reminds people that he has faced tougher foes in the past.

This may be one of McCain’s best ads of the campaign. Direct, optimistic, forceful, and serious, he’s making the case for tested leadership in a crisis.