Virginia Postrel suggests that Barack Obama’s campaign has come down to this: “Provide a noble lie that tricks us into self-improvement.” Lovely. So Democrats get to choose between Hillary Clinton, the teller of ignoble lies, and Obama, the spinner of noble ones?

At bottom, though, his lies are no more noble than hers. Bonding with Rev. Wright to solidify your credentials in the black community while playing on whites’ hopes for a post-racial society is not noble, it is deceitful. Remaining sufficiently slippery to let everyone think what they want about your policies (whether on trade or Iraq) is not noble, it is political cowardice. And a recipe for disaster: as President, you have to be at all times clear and forthright with allies and opponents domestic and foreign. But what about this notion that we will all be improved by choosing him as President? How and why will this happen, exactly? What is the substance of this “improvement”?

No one has been able to answer that question satisfactorily yet. So it’s not surprising that Obama’s poll numbers are down, but that Clinton has not benefited by his slippage. It is a tough choice. If this is a contest to find the most “authentic” candidate, I can see how Democratic voters are stumped.