Why Do Lefties Hate Tax Cuts on the Rich?

Reading Tim Pawlenty’s paean to double plus supply-side-ism yesterday made me wonder, once again, why conservatives think we liberals are opposed to it. I mean, if it actually worked, why would we be? It’s politically popular, and by their accounts it would generate trillions of dollars in extra revenue that we could use to finance our beloved lefty social programs. What’s not to like?

The only answer I can come up with is that conservatives are now completely invested in their theory that we liberals loathe rich people so much that we don’t care. We all want to screw the wealthy so badly that we’re willing to forego the elections we’d win and the mountains of revenue we’d gain if we lowered their taxes. We hate them that much.

Or is there some other wacky theory that’s popular in conservative circles but that I’m unaware of?