The Obama campaign just released a memo that constitutes its most extensive attack by far on Mitt Romney’s years at Bain Capital. The timing is very interesting: Rather than continue to let Republicans tear into Romney’s record, the Obama campaign wants to put its own stamp on this rapidly evolving narrative.

To that end, the memo devotes extensive space to rebutting Romney’s primary argument about Bain — one echoed in a new Romney ad this morning — that Dems and Republicans who are raising questions about those years are putting “free enterprise on trial.” This suggests the Obama team recognizes this as a potentially persuasive argument about the President that needs to be knocked down right away. Key nugget:

Romney closed over a thousand plants, stores and offices, and cut employee wages, benefits and pensions. He laid off American workers and outsourced their jobs to other countries. And he and his partners made hundreds of millions of dollars while taking companies to bankruptcy.

Although some of the businesses in which he took a stake undoubtedly added jobs, neither Romney’s campaign nor any independent fact checker has supported his claim of producing a net increase of 100,000 American jobs — or even anything close to it.

That is Romney’s record. His overwrought response to questions about it has been to insist that any criticism of his business record is an assault on “free enterprise” itself.

But this is just an attempt to evade legitimate scrutiny of the record on which he says he’s running. “Free enterprise” isn’t running for President, Mitt Romney is....

Our economic crisis and endemic income inequality were caused in large part by a few who put profits over people...Between now and November the American people will decide whether to respond to this crisis by electing a corporate raider who profited from — and promises to restore — the conditions that caused it, or re-electing a President fighting to level the playing field for American businesses, restore fairness for consumers and help the middle class reclaim a sense of economic security that will benefit the entire economy. That’s what’s on trial, not “free enterprise.”

The memo doesn’t mention it, but the argument that raising questions about Bain does not constitute an attack on “free enterprise” itself is supported by Sarah Palin, Newt Gingrich, Rick Perry, Bill Kristol, and writers at National Review and Daily Caller. The GOP is on the verge of nominating someone who is to the extreme right of even some leading Republicans on the morality and practicality of unfettered profit-driven free market capitalism, the topic that will perhaps be more central than any other to the presidential campaign.

What you see above are the battle lines that will define our politics for the next 10 months.