The candidate: President Obama.

The ad: The two-minute ad focuses on GS Technologies, a steel mill in Kansas City, Mo., that went bankrupt in 2001, eight years after it was bought by Bain Capital, the private equity firm that Mitt Romney co-founded. (Watch the spot below.) Several former GS workers interviewed in the spot paint Romney as a "job destroyer" and a "vampire" who "sucked the life" out of the company, and "walked away with millions." In the closing seconds, one man says, "If he's going to run the country the way he ran our business, I wouldn't want him there. He would be so out of touch with the average person in this country."

The ad buy: A GOP source told Politico that the Obama campaign is "only spending $71,000" to air the ad in five states. That includes $6,700 in Virginia, $52,400 in Ohio, $7,900 in Pennsylvania and $2,000 each in Colorado and Iowa. Viral online viewings come free.

The strategy: This is the first Obama ad to attack Romney's business record, says Rachel Weiner at The Washington Post, but this isn't the first time Romney's tenure at Bain has been brought up in the presidential campaign. Team Obama is just picking up where former House Speaker Newt Gingrich and Texas Gov. Rick Perry left off in the GOP primary fight, undermining Romney's "central claim that his business experience qualifies him to turn the American economy," says Mara Liasson at NPR.

The reaction: Although the trial-balloon ad aired for just one day (an accompanying website is still live), it caused a huge stir: Politico's Alexander Burns described it as "brutal," while even former Obama administration adviser Steve Rattner called the spot "unfair." Critics questioned the ad's accuracy: "The ad fails to make clear that the Kansas City plant was already facing hard times, and Bain Capital's investment may have represented its best chance for survival," says Glenn Kessler at The Washington Post. Still, "Bain reaped a substantial return on its investment — at least $12 million — while the company's debt burden soared to $378 million." The Romney campaign sarcastically welcomed Obama's "attempt to pivot back to jobs," and reiterated its stance that "Mitt Romney helped create more jobs in his private sector experience and more jobs as Governor of Massachusetts than President Obama has for the entire nation." 

The fallout: Romney's camp quickly released a decidedly tame web-only response ad championing the success of another Bain Capital steel company, Steel Dynamics. But Obama should prepare for a harder-hitting response from Romney supporters: According to The Associated Press, Crossroads GPS, a pro-Romney independent group, will launch a $25 million month-long ad war "that castigates Obama on the economy by using his words against him."

Sources: Washington Post (1, 2), Politico NPR, Wall Street Journal