In the wealthiest suburbs of Virginia, a quiet revolution was under way yesterday as life-long republicans switched sides to vote for Barack Obama in the Democratic primary.

So deep is the disillusionment with George Bush, so uninspiring the choice offered by the Republicans, that many life-long conservatives are abandoning the Grand Old Party to support a liberal black candidate.

Even Colin Powell, who served in two Bush administrations, has let it be known that he is considering voting Democrat. "Every American has an obligation right now at this moment in our history," Mr Powell said at the weekend, "to look at all the candidates and to make a judgement not simply on the basis of ideology or simply on the basis of political affiliation, but on the basis of who is the best person for all of America."

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Laura DeBusk, 37, a "stay-at-home-mom", is one of the refuseniks who turned out yesterday for Mr Obama across Virginia, Maryland and Washington DC. In the past two presidential elections she voted for George Bush in the belief that he could best protect America from terrorists. It is a choice she now bitterly regrets.

But she has been inspired by Mr Obama's offer to bring together Americans from all political persuasions: "A friend of mine called me up after she heard I was for Obama," she said. "She told me she was as well. 'We're the Obama-mamas,' she told me. And it's true. He is so inspiring we are going to volunteer for his campaign."

Along with many of her friends, Ms DeBusk has broken with the GOP for now. She is angry with Mr Bush over the war in Iraq, the state of the economy and the damage done to America's reputation.

"You never know what somebody is going to do in the White House, but to me Barack Obama is a breath of fresh air," she said while heading out the door to cast her first vote for a Democrat in the Virginia primary. "He just doesn't seem beholden to anyone.

But if Mr Obama is denied the nomination, Ms DeBusk will not be supporting Hillary Clinton. "She is just too polarising, too divisive," she said. "I will vote for McCain instead. He's a decent man even if he is less inspiring."

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