Ezra Klein ponders Obama's new line of attack:

Obama is trying to increase the visibility of Ryan’s budget. He’s attacking it precisely because that will make Republicans rally around it. He’s trying to make everyone agree that Ryan’s budget is the Republican agenda. And, ultimately, he’s trying to make Romney answer for it. If the White House has its way, they’ll spend the rest of this year campaigning against Paul Ryan even as they run against Mitt Romney.

Frum agrees that Obama is planning on campaigning against Ryan and that "Republicans have decided to make it as easy as possible for the Democrats to do it." First Read considers the GOP's response:

Their reaction seemed to be: How dare the president campaign against us!!!! And as we pointed out yesterday, Obama isn’t necessarily running against Mitt Romney; he’s running against the Republican Party brand — and making sure that Romney owns that brand. In fact, Romney’s biggest challenge over the next two or three months will be for him to differentiate himself from the brand. There’s been a lot of focus of late on how damaged Romney has become in this process (his high negatives with indies, etc). But we’ve noticed a larger trend: The brand of the GOP is what’s been damaged; Romney may simply be collateral damage. And this is why he has to figure out a way to either improve the GOP’s brand or differentiate himself. Which can he achieve?

Paul Ryan's response to Obama is here.