These days, the battle between Barack Obama and Hillary Rodham Clinton is mostly about electability, about who has the better chance to win in the fall.

And both sides have an argument to make - having to do with the electoral map, among other things - which hasn't always been the case.

For much of the campaign for the Democratic presidential nomination, electability was Obama's strong suit.

He was the one bringing in new voters and beating Republican John McCain in polls, while she was seen as carrying too much political baggage.

That's changed to some degree recently, with the revelations about Obama's past associations and Clinton's continued success in the larger states, including Pennsylvania.

"This is, for me, a no-brainer," said Ohio Gov. Ted Strickland, calling Clinton the candidate with "the greatest strength in the states that are necessary to get us the electoral votes that we need."

Countered Obama's campaign manager, David Plouffe, speaking Friday on the program National Journal on Air: "The real question is: Who can appeal to independents? . . . Who can bring out younger voters? Who can create a favorable turnout dynamic?"

Current polls offer no help to superdelegates or primary voters in trying to figure this out. Most show Clinton and Obama both running about even with McCain.

So what factors constitute electability?

Electability has a lot to do with who these candidates are, which means it has a lot to do with gender and race. Those two factors permeate every aspect of the contest.

But at least four other elements are involved in the electability equation, and all of them cut both ways.

They are geography, the strength and loyalty of various voting blocs, the vetting of the two candidates, and the value of experience as opposed to freshness.

Political geography. This factor seems to get the most attention.

After the votes for Pennsylvania were counted, New Jersey Gov. Corzine wondered aloud why Clinton was not the obvious nominee after having won virtually every big state that Democrats want or need in the fall.

Clinton has won primaries in California, New York, New Jersey, Pennsylvania, Ohio, Michigan and Florida. The list makes quite a political statement, although the statement falls apart somewhat on closer examination.

Two of the big states, California and New York, are virtually certain to go Democratic in the fall, no matter who the nominee is. The same can be said of Illinois, which Obama won.

Michigan and Florida come with asterisks attached because the results there have not been recognized by the Democratic National Committee.

In addition, there's not much historical evidence of a direct link between carrying a state in a presidential primary and winning it in November. So it's not a given that Clinton would win Ohio and Pennsylvania in the fall.

Even with those caveats, Clinton does have a geographic argument to make about electability - and it's not just that she does better against McCain in Pennsylvania, Ohio and Florida in the polls.

Look at the places Democrats must win this year - or have a plausible shot at winning - if they are to get to the magic number of 270 electoral votes: the 28 states, plus the District of Columbia, that Sen. John Kerry won in 2004 or came within 10 percent of doing so. They represent 355 electoral votes.

In the primaries thus far, Clinton has won 11 of those states representing 178 electoral votes - 13 states with 222 electoral votes if Michigan and Florida were included.

Obama has taken 15 for 126 electoral votes. One state, Oregon, has yet to vote.

The counter from the Obama camp is that he's better positioned to extend the Democrats' playing field in the West by attracting independents and in the South by raising black turnout. Plus, polls show him running stronger in numerous states, including Colorado, Connecticut, Iowa, Minnesota, New Mexico, Nevada, North Carolina and Washington.

Voting blocs. Throughout the primaries, Clinton has done well with white women, older people, Latinos, Catholics and blue-collar workers. Obama has won among blacks, the young, independents and college graduates.

Looking toward the general election, the question is which candidate has the more valuable coalition - and which nominee would be embraced more (or abandoned less) by the losing candidate's supporters.

Clinton's blocs include the voters who Mark Penn, her former chief strategist, has said cost Kerry the presidency in 2004, namely Latinos and "security moms." Also in the Clinton camp are many of the voters once known as "Reagan Democrats," more of whom might defect to McCain in the fall if Obama were the nominee.

On this score, Clinton looks more electable in Pennsylvania at the moment.

In exit polling last Tuesday, 24 percent of primary voters said they wouldn't support Obama in the fall, while only 17 percent said the same of Clinton. How many will feel that way come November is hard to know.

On the other hand, party leaders throughout the country have been ecstatic about the young people Obama has drawn into politics and the Republicans and independents who have voted for him.

And they're worried that those voters - plus African Americans - would feel betrayed and disillusioned if the first black candidate with a chance to be nominated appears to have been cheated out of the prize by the superdelegates.

Those concerns, about damaging the party's future and angering one of its most loyal constituencies, are likely to weigh heavily on the minds of superdelegates.

Vetting of the candidates. Clinton likes to say that she has led the most examined life of any other politician in America. The suggestion is that there won't be any damaging revelations about her between now and November.

What is known about her, though, has caused millions of Americans to rule out voting for her. According to a recent Washington Post-ABC News poll, only 39 percent of Americans said they found her "honest and trustworthy," hardly a plus for electability.

Obama has been less thoroughly vetted, making his image more vulnerable to fresh stories about his past.

During the Pennsylvania campaign, he was damaged by the appearance of the videotapes of his former pastor, the Rev. Jeremiah A. Wright Jr., shouting "God damn America!" - and by the talk during the debate in Philadelphia about his association with William Ayers, a former member of the Weather Underground, a 1970s radical group.

Were Obama to become the nominee, the election likely would turn on whether enough voters, some of whom question his patriotism, could get comfortable with the idea of having him as their president. There's no way to know what stories about him are yet to emerge.

Experience vs. freshness. Clinton's eight years in the Senate and eight years as first lady make her familiar to the electorate, which is good, or too familiar, which isn't. A lot of Democrats, and far more independents and Republicans, are tired of the Clintons.

All of this experience didn't stop her from making a political blunder last month, saying that she'd landed in Bosnia under sniper fire in 1996 when she hadn't.

Obama is a fresh new face offering what he calls a new kind of politics, which can be attractive to voters, and he's short on national experience, which can be scary. Clinton has accused him of not having passed the threshold of credibility to be commander-in-chief, while saying that she and McCain have.

The Illinois senator's political inexperience gets highlighted when he makes an unforced error, such as his statement about "bitter" residents of small-town Pennsylvania.

Of course, Obama could make himself look more electable by winning some significant primaries, something he hasn't done since Feb. 19 in Wisconsin.

He gets his next chance May 6 in Indiana and North Carolina.