The question of God’s role in American politics has not exactly been on the back burner these past few years. And so it is worth noting that God has finally made her presence felt and directly intervened in the current campaign. She has actually endorsed one candidate and is even throwing a fundraiser for him on September 8.

By God, I mean, of course, Oprah Winfrey. Who else? It is extremely hard to think of a figure who attracts more instant awe, reverence and eyeballs than the billionaire entertainment mogul. She manages somehow to transcend blue and red America, with her combination of endless compassion and sensible self-help. She is white America’s favourite black woman, and black America’s favourite mainstream star.

Her hold on the psyches of American women of all races is enormous. And the man who most needs both to reboot his Hollywood money machine and also win over more Democratic women is the man Oprah has decided to endorse for the first time in her career: Barack Obama.

The e-mail invites went out last week, promising “the most exciting Barack Obama event of the year anywhere”. Oprah’s endorsement, made on the Larry King show, was not exactly understated either: “I think that what he stands for, what he has proven that he can stand for, what he has shown, was worth me going out on a limb for and I haven’t done it in the past because I haven’t felt that anybody – I didn’t know anybody well enough to be able to say, ‘I believe in this person’.”

In a climate where endorsements don’t count for as much today as they once did, Oprah’s first is a big deal. She and Obama have an obvious connection. Oprah is based in Chicago and so is he. But more important, they are both mainstream black figures aiming for the white-hot centre of American power. They represent an era in which black America is no longer represented solely by the marginalised and the angry. They are uniters, cultural smooth-talkers, calmer-downers, self-made people in a country that has had enough of dauphins in the White House.

To be sure, Oprah went out of her way not to diss Clinton, whose support among women and African-Americans has kept Obama in a firm, water-treading second place in the polls, if not in fundraising.

“I think I’ve said this before and it’s true: because I am for Barack does not mean I am against Hillary or anybody else,” Oprah explained. “So the fact that I would endorse Barack Obama, I have not one negative thing to say about Hillary Clinton.”

That’s the classic Oprah touch: never divisive, always positive, but somehow not completely vapid. It’s not easy to pull that off and to retain an appearance of authenticity, but that’s why her talk show remains a phenomenon in the popular culture.

She has an ally among black women for the Obama candidacy. The other woman is not well known yet, but she soon will be. In some ways, she is for Obama in retail politics what Oprah is for him on the national stage. Her name is Michelle Obama, and she is the Illinois senator’s wife.

If you ransack YouTube, you’ll find some grainy videos of Michelle at largely black events, both dressing down and puffing up her husband, criticising his sloppy housework habits but always promoting his realness to black Americans.

She, unlike her husband, has no white parent. Her parents, the Robinsons, were a city pump operator and a secretary. Her brother is an Ivy League basketball coach. But like her husband, she made her way out of modest beginnings and won places at Princeton and Harvard Law School. More to the point, she never shies from these achievements and touts them to black audiences as evidence of what the future can hold.

Like her husband, she also turned her career from a lucrative law practice to public service. Her current job – apart from raising two young daughters – is in public affairs for the Chicago University hospital system. She has a reputation for extreme discipline – the gym at the crack of dawn, and, according to the Chicago Tribune, unmissable Friday afternoon hair and beauty appointments.

She’s also a woman of her generation – supportive of her husband (she was assigned to be his supervisor at the law firm where they once worked together), but also her own person.

Why am I focusing on these two women? Because, at this point, Senator Clinton’s entire advantage in the Democratic race is because of her considerable edge among Democratic women and her surprising resilience among African-Americans. The former is unsurprising. Clinton is the first serious female candidate ever to have a chance at the presidency. Her strength among blacks is arguably almost entirely a factor of her husband’s continuing appeal.

Obama’s two women can help chip away at those two pillars of Clinton support. He’s got the money and the enthusiasm, but he needs to break through with women and blacks.

Oprah is there to underline the other first in the race: a black senator with a real chance at the White House, at ease with white power but not beholden to it. Michelle is there to underline the same thing, but to add to it a clear sense that this is one black man who has married, stayed faithful and reared two daughters with a self-confident and accomplished partner.

If you’re a woman who likes Clinton in part because she represents an ability to endure the humiliation that men sometimes inflict on their spouses, then Obama is an emblem of the good husband who speaks to the same emotional impulse. Hillary is the wound; Barack is the salve.

The strange thing is that Obama needs this appeal to African-Americans and women more in the primary than in the general election. He has far more appeal to independents and Republicans than Clinton. He has a real base among the latte-swilling upper-middle classes, and a real chance of expanding Democratic party support beyond its usual base. But the core Democratic, female voter still prefers her to him. If he cannot break that pattern, he never gets to test his broader national appeal.

And that, perhaps, is the most striking thing about his candidacy so far. Yes, he has raised more money than Clinton. Yes, he is a freshman senator, not a veteran of the Washington wars for two decades. But he is also a candidate limited by the Democratic base, rather than dependent on it.

I never thought I’d write that about a black man. But that is part of the transformational potential of his candidacy. It could elbow the likes of Al Sharpton and Jesse Jackson off the stage for ever. But only if he can knock Hillary off first. That’s what Oprah and Michelle must do.

Sometimes it takes a woman. And he’s got two Amazonians on his side.

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