Washington ? It’s a day when the Bush bounce has hit Kerry supporters upside the head. The morning papers are full of polling reports that suggest the president is on a roll. The pundits are full of rumors about a Kerry campaign shake-up.

The party that came out of the Boston convention in single-file unity has returned to its default position: a circular firing squad with the campaign strategists in the middle. The partisans in the street are frantic that the Bush campaign will “do it again,” and take the low road to victory.

At the center of this September anxiety attack, campaign manager Mary Beth Cahill seems as cool as the walls in her office and as collected as her clean desktop. Behind her, a muted TV screen is on 24/7 politics and there’s a framed sentiment that you would not see in Karl Rove’s office: “To be finally alive is to work for the common good.”

Last November, when Cahill took over the campaign, Kerry was trailing Al Sharpton in South Carolina. By March, she was touted as a political Wonder Woman. Now Newsweek describes the “rap” on her as being “schoolmarmish,” fretting about “going negative” and not nasty enough to lead the campaign.

If the white-haired Cahill is ruffled, it doesn’t show. “This was sort of inevitable. Our numbers went down from the battering we took,” she says, and adds, “there’s a rhythm to these things.”

The eldest of six children in an Irish Catholic working-class family, Cahill began her career answering phones for Bob Drinan when the Boston priest was a congressman. She’s run tough campaigns for candidates like Vermont’s Patrick Leahy and is widely credited with charting a successful strategy for EMILY’s List of women candidates.

The word that people use most often to describe her is “steady.” But that doesn’t soothe a lot of those who are dismayed that Kerry got “out-toughed” by opponents who throw mud even at Purple Hearts. Indeed Susan Estrich, the campaign manager for Mike Dukakis says, “The trouble with most Democrats traditionally is that we’re not mean enough. Dukakis wasn’t. I wasn’t.”

This week’s common wisdom is that Kerry’s slow response to the scurrilous attacks of the Swift boat crowd gave the public the idea he wasn’t tough enough. If Cahill agrees now, she isn’t about to say so.

She rather describes Kerry as a man who is “polite to the core” and “deeply reserved” and “a tough guy, but tough on the issues.” She adds: “If sheer protestations of strength get you to success, then Osama would have been captured.”

If the Kerry campaign hasn’t taken the low road, it is partially because, she says, “win or lose, and my deep belief is he’s going to win, you run a campaign you live with for the rest of your life. George Bush Sr. is forever tarred by the craven way he went after Dukakis.”

But it’s also because of a strategic belief that the swing voters they need to attract — most of them women — are ultimately turned off by mudslinging. “Their entire strategy is to enlarge their base. If more evangelical Christians come out, they win. Ours includes the swing voters and the late deciding voters, and a lot of them are women.”

After I note that women have also moved toward the commander in chief, she predicts that all the numbers will change. Three days later they have. Indeed, only Time magazine now gives Bush an 11-point lead while others’ range from six points to a dead heat.

Nevertheless, 63 percent of the voters in the ABC-Washington Post poll still believe that Bush is going to win — a number that includes a whole lot of Kerry voters.

Ellen Malcolm, who has worked with Cahill since the days at EMILY’s List, says, “She stays calm when everyone else turns into Nervous Nellies. Sometimes Democrats can be way too nervous.” Maybe.

Astonishing as it may sound to the intense partisans, the very people who may determine this race may not be paying attention yet.

So Cahill, who lives politics, offers a little balance. About those undecideds, she says wryly, “The fact that I want them to decide now has no effect. They don’t feel the need to make up their minds yet. Fundamentally, voters think elections are about them, not about candidates. They want some attention to the things that make their lives easier. It comes back to jobs, health care and the possibility that they can send their kids to college.”

If anything, the past two weeks have shown that there is swing in the swing voters. The bumper sticker she would write for the Kerry campaign is “America Can Do Better.” But for now, Cahill is saying: Take a deep breath, it’s still a long way to November.