An hour ago, President Obama gave a speech attacking Paul Ryan's budget. It was a highly political speech that began with a hot mic joke and quickly built to this attack on Mitt Romney and Newt Gingrich:

It's smart for the president to put the Republicans on the defensive on a primary day, and it's also smart for him to attack the Ryan budget. Presumably, these attacks are going to force Romney to tie himself even harder to a budget that slashes Medicare and Medicaid and Social Security, thereby weakening his second-strongest base—old people. (Romney's strongest base, of course, is the 1% and, if we're counting them as people, corporations.) When presidents speak, every single one of their words have power. Obama mentioning Ryan so frequently and so pointedly automatically bumps him up a slot or two on the vice presidential shortlist for Republicans, too.

And this is exactly the kind of message that the president's campaign needs to deliver every day between now and November:

“This congressional Republican budget … is something different altogether. It’s a Trojan Horse...Disguised as deficit-reduction plan, it’s really an attempt to impose a radical vision on our country. It’s nothing but thinly-veiled Social Darwinism. It’s antithetical to our entire history as a land of opportunity and upward mobility for everyone who’s willing to work for it - a place where prosperity doesn’t trickle down from the top, but grows outward from the heart of the middle class. And by gutting the very things we need to grow an economy that’s built to last - education and training; research and development - it’s a prescription for decline.”

If Democrats can keep the conversation on Ryan's budget this year, there could be huge wins for the whole party in November. Expect the Republicans to try to change the conversation as quickly as they can to anything else, while still trying to defend the budget even as they retreat.