Probably when he's been in office long enough for anything to have had an effect

Bush was still blaming Clinton 3 years in.

I should add to this that he was probably right to do so too. Anyone who thinks that a country's economy, budget, deficit, etc. will turn around in a matter of months is plain naive. Things like that take years to change the current trends and as such EVERY administration inherits the leftovers from the one before it.

Clinton inherited a big deficit and the leftovers of a war. He did turn the economy around but in turn let some foreign policy issues slide.

Bush inherited a budget surplus, the beginnings of a mild recession, and a poor security policy. He got blindsided by 9/11 which wasn't his fault. He in turn beefed up the country's security but completely tanked the economy in the process. At the end of it don't forget he drafted the initial stimulus package.

Obama in turn inherited a tanked economy that was on a fast downhill slide and that isn't going to turn around any time soon no matter what he does. He also inherited 2 wars, one of which he doesn't think you should be in. I honestly believe IF his policies have any net effect it won't happen until after he's gone anyhow because the US is fairly royally screwed in the money department no matter how you slice it.

If anyone thinks this could be fixed in one term, let alone one year... or probably even one decade... I'd really like a hit off whatever you're smoking. Every administration inherits crap from the one before. It's been like that since Ure blamed Ogg for the fact their Neanderthal tribe was living too far from the river.