You know what, I will do you one better in terms of optimism - Obama is teflon. Attacks just do not stick to him. As such, the Republicans will take this approach in the fall and it will fail, but its failure will have nothing to do with Sen Clinton's futile attempt to use the strategy earlier. It is not that voters will be immune to this by virtue of exposure - it is just that Sen Obama is such a strong candidate that he can fend off these attacks even when they are brand new and at full potency.