Santorum lets his resentment against Romney get the better of him (via Andrew):

If you look at where my Republican opponent has won, it’s always in and around the cities. It almost looks like a Republican versus a Democrat.

I understand why Santorum thinks this is a clever line, but it isn’t clever. What he is saying here is that Romney wins the areas that have the most people in them, which is why Romney has received over a million more votes than Santorum. He is announcing that Romney does best in the areas where the vast majority of Americans lives. Santorum is unwittingly making the argument for Romney’s electability in the fall while undermining the case for his own (if such a thing exists). This does “tell us something,” but it doesn’t tell us what Santorum wants voters to believe. Santorum is boasting that even among Republican primary voters he underperforms in those parts of the country that are essential to a general election victory. He might as well have declared, “Behold how limited my national appeal is!”