WASHINGTON — The presidential campaign of Sen. Barack Obama for the first time criticized Sen. John McCain for his role in the "Keating Five" savings-and-loan scandal yesterday, saying the issue was fair game after a weekend of attacks by Alaska Gov. Sarah Palin over the Democrat's ties to Vietnam-era radical William Ayers.

Attempting to link the early-1990s scandal to the current economic crisis, the Obama campaign launched a Web site devoted to "Keating Economics," including a documentary-style video of McCain's involvement and news clips of his Senate testimony. The collapse of Charles Keating's thrift cost taxpayers billions and required a large government bailout package.

The campaign also sent an e-mail to millions of supporters arguing that then, as now, the Republican lacks judgment on financial oversight during a crisis.

"With so many parallels to the current crisis, McCain's Keating history is relevant and voters deserve to know the facts — and see for themselves the pattern of poor judgment by John McCain," Obama's campaign manager, David Plouffe, wrote.

At his own campaign event hours later, McCain sharply questioned Obama's character and intentions, telling a crowd in New Mexico that "even at this late hour in the campaign, there are essential things we don't know about Sen. Obama or the record that he brings to this campaign."

"All people want to know is: What has this man ever actually accomplished in government? What does he plan for America?" McCain said. "In short: Who is the real Barack Obama?"

The attacks represented some of the strongest language yet in a race that has grown increasingly negative and signaled that the final four weeks of the campaign could grow even nastier.

McCain senior adviser Nicolle Wallace defended Palin, dismissing the suggestion that the vice presidential nominee was overstating the relationship between the two men when she accused Obama of palling around with a former terrorist.

Raising the Keating scandal fulfilled a promise by the Obama campaign to revive the matter if they felt the McCain campaign ventured too far down the path of personal attacks.

The McCain campaign pushed back hard yesterday against Obama's charges, arguing that the Arizona senator was treated unfairly by the Senate ethics investigation and asserting that McCain had been much more open about his relationship with Keating than Obama has been about his connection with Ayers.