Click here to watch "His Choice."

Barack Obama is set to air a 30-minute infomercial/campaign ad on network TV at 8 p.m. tonight. But that does not mean his campaign is letting up on its more traditional 30-second spots. Obama has released several new ads in "key states" this week, attacking John McCain on economic issues and touting his own proposals.

In "Tested" (subscription), the Obama camp responds to the controversy over comments by vice presidential candidate Joe Biden at a recent campaign fundraiser, in which he suggested that America's foes would initiate some kind of crisis to "test" Obama within his first six months of office.

"An economic meltdown. Two wars. And John McCain’s playing with audio tapes," an announcer charges, accusing McCain of distorting Biden's message in "Ladies And Gentlemen" (subscription), released last week. The announcer acknowledges that the "next president" will, in fact, "be tested" (implying that it is irrelevant whether Obama or McCain is elected), but he then introduces another part of Biden's comments left out of the McCain ad, in which the Delaware senator says that those who do "test" Obama will "find out this guy’s got steel in his spine."

Citing quotes from several newspaper editorials, the spot goes on to compare Obama's and McCain's reactions to the economic crisis, saying Obama has shown a "steady hand" while McCain has been "erratic." The real "risk" the country faces, the announcer concludes, is electing a president whose "policies follow in [President] Bush’s footsteps."

"His Choice" (subscription) also portrays McCain as inadequate to the task of fixing the economy, but goes a step further with a swipe at the GOP candidate's running mate, Sarah Palin. In this ad, text of three different McCain quotes appears on screen. ""The issue of economics is not something I've understood as well as I should," reads one. The next says: "I might have to rely on a vice president that I select" for expertise on economic issues. Footage of Palin winking into the TV camera at the vice presidential debate appears, with the words "His choice?" superimposed.

Finally, "Better Off" catalogs the myriad economic challenges -- foreclosures, rising unemployment, falling wages -- facing Americans right now. "For too many, the American dream is fading," Obama chimes in, seeking to identify with working- and middle-class voters. "We need a new direction. Now. And that's why I'm running for president," he says directly into the camera.

Obama plans to use his half-hour spot tonight to make a "closing argument" to the American people, and such messages, focused on helping the middle class and changing the direction of the country, are sure to be at the heart of the address.