The outcome in today's Magnolia State primary is unlikely to surprise anyone. Unless the laws of politics--and mathematics--suddenly collapse in on themselves, Barack Obama should defeat Hillary Clinton by relatively wide margin. Five polls taken over the last week show Obama leading Clinton by an average of 18 points; on March 6 an InsiderAdvantage survey posted a smaller spread of plus six for Obama--spurring stories like this--but by March 9 the public opinion firm had him up by nearly 20. The major reason for Obama's lead: a Democratic electorate that's 56 percent African-American. When blacks, who typically vote for Obama four- or five-to-one, make up a majority of voters, as they did in Georgia (51 percent), Alabama (51 percent) and South Carolina (55 percent) it's very, very hard for anyone else to win--let alone come close. 

That said, if you can tear yourself away from the coverage of Eliot Spitzer's sex scandal, Mississippi is still worth watching. Three thing to track:

1) The Delegate Count: As we've repeated ad nauseam, Obama's case for the nomination at this point is all about math: I am winning by 100-plus delegates, he says. No matter what happens in the upcoming contests, I will still be ahead in the delegate count by the end of regulation. If things go as planned today, his campaign could emerge with a new arithmetical talking point. On March 4, Hillary Clinton won the primaries in Texas, Ohio and Rhode Island, giving her a ton of narrative momentum--"Comeback Kid," anyone?--but only a tiny net gain in delegates. Ohio awarded her nine more delegates than Obama, but his victories in Vermont and the Texas caucuses canceled out her primary wins in Rhode Island and the Lone State State. With two delegates from Saturday's Wyoming win, that means Obama has a chance to completely erase Clinton's March 4 advances today. According to Slate's Delegate Calculator, a 20-point win net him the seven delegates needed to do the trick--which is exactly what the polls are predicting. So keep an eye on that margin. Of course, a nifty mathematical "triumph" won't trump Clinton's comeback storyline, or shift the spotlight off of Pennsylvania. But it's definitely the factoid that Team Obama is hoping to feed the talking heads tonight.

2) The Black Vote: Back in August, Obama told the AP that he's the "only candidate who, having won the nomination, can actually redraw the political map." The reason? Black voters. "I guarantee you African-American turnout, if I'm the nominee, goes up 30 percent around the country, minimum," he said. "So we're in a position to put states in play that haven't been in play since LBJ." The state at the heart of Obama's prediction was Mississippi. At the time, Obama said that "if we just got African-Americans in Mississippi to vote their percentage of the population, Mississippi is suddenly a Democratic state"; in November he told the Washington Post that he "think[s] [he] can put Mississippi in play." Today will be the first test of Obama's clairvoyant "30 percent" claim--and he's not likely to pass.  African-Americans made up 56 percent of Magnolia State's Democratic primary electorate, meaning that a 30 percent increase would boost black turnout to a preposterous 73 or 74 percent. As leading scholar of black politics David Bositis told me in November, "no state and no voting group has a turnout of 74 percent." *** Rather than mess up the math myself, I'll quote Philip Klinker of PolySigh:

In 2004, blacks made up 34 percent of Mississippi's electorate and gave 90 percent of their votes to John Kerry. Conversely, whites made up 66 percent of the electorate and gave 85 percent of their votes to George W. Bush. Based on that breakdown of votes, blacks would have to make up 47 percent of the electorate in order for the Democratic candidate to win the state. In 2004, there were 1,152,365 votes cast in Mississippi in the presidential election, 66 percent or approximately 760,561 by whites. Assuming that the white vote remains the same, there would have to be approximately 675,000 black voters in order for them to make up 47 percent of the electorate. According to the Census, there were only 698,000 voting age blacks in Mississippi in 2004. Even accounting for changes in population over the last four years, a Democratic win in Mississippi this November would require a black turnout of nearly 100 percent. 

So don't hold your breath. That said, Obama has been increasing black turnout across the deep South; in the Palmetto State primary, for example, it was up about 17 percent over 2004. And the Obama camp would argue, I'm sure, that the dynamics in a primary are totally different than the dynamics in a general election. With that in mind, I'll be keeping an eye--if a wary one--on black turnout.

3) The Republican/Independent/White Vote: There's another reason to doubt that Obama could put Mississippi, which voted for Bush 60-40 over Kerry in 2004, into play this November: racial polarization. "Anything in Mississippi that would so animate black voters would probably have the effect of animating white voters in the opposite direction," Bositis told me back in November. The pre-primary polls suggest that he's right. Obama typically loses white voters to Clinton by five to 20 points; in the latest InsiderAdvantage survey, he loses by 53. Similarly, Obama's traditional edge among Republicans and Independents--often two- or three-to-one--is reduced in the poll to deficits of 68-29 percent and 53-23, respectively. And this is among likely Democratic primary voters. Needless to say, such "Deep South" margins don't bode well for Obama's chances with the general electorate, which was 47 percent Republican and 63 percent white in 2004. It'll be interesting to see if they hold up tonight--and possibly help Clinton finish stronger than expected.

***As reader Darlene Easson of Mississippi notes:

I think the Obama 30% argument is that the black turnout would be up 30% over what it was, not of its percentage overall.  So lets say 20% of the registered black voters actually voted in the 2004 Mississippi primary (primary turnout was somewhere around 10% in 2004, so I'm being generous here).  Up that by 30%, and you're at 26% black turnout.  Given that 6% increase, and figure it will largely go Democratic, it would certainly pump up the Democrats chance at taking Mississippi in November.

She's absolutely correct. I was going off of David Bositis's math--which is clearly flawed. I've changed the passage in question to reflect, um, reality.