Related: A new poll forecasts the Democrats’ chances against McCain. Update: The first poll to crunch the electoral math just came out.

WASHINGTON — Hillary Clinton is not the only Democrat with a math problem. But the arithmetical difficulty that Barack Obama faces is fundamentally different from Clinton’s: She doesn’t have the numbers that plot a clear path to the nomination; he doesn’t have the numbers that plot a clear path to a Democratic victory in the fall.

The spin-of-the-day from the Obama campaign on the morning after Clinton’s victories in three of the four states holding primaries Tuesday was that the New York senator cannot possibly overtake her rival’s lead in “pledged” delegates — that is, those won in primaries and caucuses — and therefore has no chance of winning the Democratic nomination.

The arithmetic conveniently leaves out an essential part of the equation: Neither Obama nor Clinton can secure through the primaries and caucuses the 2,025 delegates necessary to win at the Denver convention without the votes of the superdelegates. And Clinton’s stunning performance Tuesday, particularly in Ohio, makes Obama’s argument that superdelegates should automatically back the will of the voters — and not use independent political judgment about who can best compete against Republican John McCain in November — look like an awfully simplistic calculus.

Add up all the states he has won in his historic drive to become the nominee, including all of those small and deeply “red” Republican states where the Obama supporters boast of their candidate’s transcendental appeal, and so far Obama has won in places representing 193 of the 270 electoral votes needed to win the presidency. Add up Clinton’s victories thus far and she has triumphed in states representing 263 electoral votes.

Of course, some states in Clinton’s column — Texas comes most readily to mind — that have a large trove of Electoral College votes are highly unlikely to wind up Democratic in the fall. But the same holds true for Obama, whose strength in Southern Democratic primaries has rested on the huge margins he has run up among African-American voters. African-Americans are a crucial constituency for Democrats, but their votes in recent contests haven’t been enough to win such states as Alabama, South Carolina or Georgia.

In a new memo, Clinton strategists Mark Penn and Harold Ickes point out that the 2004 Democratic nominee, John Kerry, lost these states and several others in which Obama has won primaries by 15 points or more. In Utah, Idaho, Nebraska, North Dakota, Kansas and Alaska — all states the Obama forces point to with pride as evidence of an emerging “50-state strategy” — no Democrat has won the general election since 1964.

So how has Obama fared in those states that are the crucial building blocks of a Democratic general election strategy? He’s won his home state of Illinois, plus Wisconsin, Washington and Minnesota. Together, these states account for 51 electoral votes. Clinton has won her home state of New York, as well as California, New Jersey and Michigan, representing a total of 118 electoral votes. This sum deliberately leaves out Ohio and Florida, which will be hotly contested in the fall.

There is a reason some states are called general election “battlegrounds.” It is because partisan identification is roughly even, or because certain groups in the electorate, such as Catholics, Hispanics or blue-collar whites, switch their allegiances — or split their votes. That’s why Clinton made so much in her victory speech about the “bellwether” nature of Ohio: “It’s a battleground state. It’s a state that knows how to pick a president. And no candidate in recent history, Democrat or Republican, has won the White House without winning the Ohio primary,” she said.

There is no papering over the depth of the problem Obama faced there. He won only five of the state’s 88 counties, an inauspicious foundation for a general election campaign. Clinton trounced him among Catholic voters, 63 percent to 36 percent, according to exit polls. She beat him among voters in every income category and bested him by 14 points among those making less than $50,000 annually.

This is why Pennsylvania, which is demographically similar to Ohio — and a must-win state for Democrats in November — is considered such fertile ground for Clinton on April 22.

The Democratic Party is indeed developing a general election problem, and it’s only partly because Obama and Clinton will be sniping at one another for the next seven weeks. Obama, the leading candidate, still hasn’t shown he has appeal in a large battleground state that will be pivotal in the fall. In this sense, Pennsylvania is where Obama’s back, and not Clinton’s, is up against the wall.

Marie Cocco’s e-mail address is mariecocco(at)

© 2008, Washington Post Writers Group

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