As you’ve no doubt heard, the Clinton campaign is arguing that Sen. Barack Obama’s (D-Ill.) inability to overcome Sen. Hillary Rodham Clinton’s (D-N.Y.) lead in Pennsylvania means he can’t win critical states like Pennsylvania and Ohio. But it’s simply a fallacy to claim that winning a state’s Democratic primary means you’re more likely to win that state in the general election or that your opponent can’t win it.

The dynamics are simply different between general elections and primaries. You have on the one hand patterns and preferences that Democratic voters show for different candidates in Democratic primaries.

Then you have the separate question of whether these same voters will vote for the Democratic or the Republican nominee in the general. One is simply not predictive of the other. It could be — if one candidate’s voters simply refuse to vote for the other candidate. But who wins a primary doesn’t tell you that.

Nor is it a big mystery that the argument doesn’t hold up because it wasn’t devised or conceived as an electoral argument. It’s a political argument — one that only really came into operation at the point at which the Clinton campaign realized that it was far enough behind that its path to the nomination required making the argument to superdelegates that she’s electable and Obama is not.

That’s not to say there isn’t a difference between the two as general election candidates — at least in their current incarnations. There is. It’s just not this big-state nonsense.

Quoted in The New York Times, Democratic pollster Peter Hart — who, for what it’s worth, is actually part of the same polling firm as Hillary’s new pollster/strategist Geoff Garin (though himself not working with either candidate) — came much closer to the mark when he said, “Hillary goes deeper and stronger in the Democratic base than Obama, but her challenge is that she doesn’t go as wide. Obama goes much further reaching into the independent and Republican vote, and has a greater chance of creating a new electoral map for the Democrats.”

That’s the essence of it. But there’s actually a little more than that when you combine that partisan analysis with a geographical one.

There’s not a lot of good or consistent polling state by state yet. But I’ve been looking at what polling data is out there. And Clinton is running a bit better against McCain in the Rust Belt states that sit just above the Mason-Dixon line. That’s principally Ohio and Pennsylvania.

But this isn’t the whole story.

In a whole arc of territory stretching from the Great Lakes through the upper Midwest down into the inter-mountain West, Obama consistently runs stronger than Hillary. Some of these states are ones Democrats really must win in order to win a general election — states like Iowa, Wisconsin and Michigan.

Others are red states that have been trending blue but which Obama appears able to put in play while Hillary can’t.

Colorado is a good example.

The last four polls of the state show Obama tied or ahead of McCain while McCain beats Hillary handily.

The most recent poll — April 21 — has Obama beating McCain by three points while McCain is beating Hillary by 14 points.

Given the spottiness of state-by-state polls, for now it’s best to watch the national popular vote polls, which show the two Democrats basically even in how well they’d fare against McCain. But there are differences.

They run better in different parts of the country. But the big-state argument is just malarkey, an artifact of the spin necessities of the post-Super Tuesday campaign.

Marshall is editor of talkingpointsmemo.com .  His column appears in The Hill each week.  E-mail: This email address is being protected from spam bots, you need Javascript enabled to view it