SUSA did some pretty kick-ass polling of all 50 states, matching up Hillary Clinton and Barack Obama against John McCain. The results?
McCain 262 McCain 258
Clinton 276 Obama 280
They both do it differently.
.....In all, Obama outperforms Clinton in 33 states: Alaska, Arizona, California, Colorado, Connecticut, Delaware, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Maine, Maryland, Michigan, Minnesota, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, North Dakota, Oregon, South Carolina, South Dakota, Texas, Utah, Vermont, Virginia, Washington, Wisconsin, and Wyoming.
Clinton outperforms Obama in 15 states: Alabama, Arkansas, Florida, Kentucky, Louisiana, Massachusetts, Mississippi, Missouri, New Jersey, New York, Oklahoma, Pennsylvania, Rhode Island, Tennessee, and West Virginia.
They are even in: Kansas and Ohio.
Now New Jersey, Washington, and maybe even Pennsylvania are teases to the GOP. They seem to consider flipping, then never do. Obama getting North Dakota is so implausible that I'd never count on it.
Ohio gives Obama and Clinton even numbers, so the notion that her victory there makes her "more electable" there is pretty silly. The same way that Obama winning Missouri doesn't make him "more electable" in that state.
All in all, it's one poll. And if polls are correct 95% of the time (which is standard), then we have to assume by definition that 2-3 of these are off. So take with all the appropriate grains of salt.