A new Zogby poll seems to provide evidence of Barack Obama’s electability advantage over Hillary Clinton and John Edwards.

In head-to-head match-ups, Hillary loses to three Republicans: Rudy Giuliani beats her by four points, Mike Huckabee by five, and John McCain by seven. She leads Mitt Romney by two and Fred Thompson by seven.

Edwards loses to two of the Republicans: Giuliani edges him by a point, and McCain by four points. He beats Huckabee by six points, Romney by 12 and thrashes Thompson by 16.

Only Obama beats all five Republicans. His closest match-ups are against McCain, whom he beats by four points, and Huckabee, whom he leads by five. He tops Giuliani by nine, Thompson by 16 and Romney by 18 points.

The difference: Independent voters. Against Giuliani, Hillary wins independents by just one point. Obama’s margin? Twenty-five points.

Of course, these polls are sort of all over the place, and Edwards has been pointing to polling recently that showed him as the electable one. But still, this is an interesting one.