Barack Obama's allies warn that John McCain's attacks on the Democrat's character will lead to the political equivalent of mutual assured destruction: Fire your big weapon at your own peril.

ASHEVILLE, N.C. — Barack Obama’s allies warn that John McCain’s attacks on the Democrat’s character will lead to the political equivalent of mutual assured destruction: Fire your big weapon at your own peril.

Several Obama surrogates said his supporters may start reminding voters of McCain’s ties to Charles Keating, a convicted savings-and-loan owner whose actions two decades ago triggered a Senate ethics investigation that involved McCain as one of the “Keating Five.”

The warnings of massive retaliation came as McCain’s running mate, Alaska Gov. Sarah Palin, took on the role of attacker and said that Obama sees America as so imperfect “that he’s palling around with terrorists who would target their own country.” She was referring to an early Obama supporter, 1960s radical Bill Ayers, a founder of the Weather Underground whose members were blamed for several bombings when Obama was a child.

Palin defended her claim Sunday, saying the issue is “fair to talk about.”

Obama has denounced Ayers’ radical views and actions. On Sunday, Obama dismissed the criticism from the McCain campaign, leveled by Palin, as “smears” meant to distract voters from real problems such as the troubled economy.

Democrats were well-synchronized Sunday, using the word “erratic” and Keating’s name in nearly matching sentences across the talk-show circuit.

“This is going to be a month, I think, of character assassination,” Sen. Dianne Feinstein, D-Calif., an Obama supporter, said on CBS’ “Face the Nation.”

Indeed, McCain adviser Greg Strimple predicted “a very aggressive last 30 days” of the campaign.