At the heart of Rick Santorum’s campaign is a simple but compelling pitch: He’s a rock-ribbed conservative with a proven record of winning in a swing state.

That much is true.

But there’s one big flaw in his claim: His landslide defeat in his last race, the 2006 Pennsylvania Senate contest, undermines this central message of his surging presidential bid.

Yes, Republicans faced a toxic political environment that year, and Santorum, in hindsight, stood little chance of survival as a top GOP Senate leader in Washington who refused to distance himself from an unpopular President George W. Bush and his equally out-of-favor Iraq War.

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