I should preface this item by noting that all my writing about pure horse race politics, and presidential primary politics especially, is highly speculative. Public policy is something that can be analyzed with some precision. Elections are highly unpredictable. It can be (hopefully) interesting and fun to speculate, but the speculation should be taken with a grain of salt. For instance, I've been predicting for months and months that Mitt Romney is a dead man, but I'm a lot more likely to be wrong about that than, say, whether the aggregate income of the richest 10% of the public is greater than or less than the budget deficit.
Anyway, caveats aside, it occurs to me that Donald Trump's implosion still leaves a huge opportunity on the Republican right. Trump was a horribly, horribly flawed messenger -- his past was filled with support for Democratic politicians, causes like single-payer health insurance, and he horrified Republicans in his high profile first speech in Las Vegas by dropping a series of f-bombs. But Trump's message itself was deeply powerful. There remains a powerful demand for a candidate to fill it.
Meanwhile, the moderate wing of the GOP primary electorate is being over-serviced. Mitt Romney and Tim Pawlenty are running, Jon Huntsman is drawing some decent press, and Mitch Daniels might jump in. That is a lot of competition for the establishment vote. It could take a while for one candidate to emerge from this group, and they could easily crowd each other out long enough so that none of them consolidate establishment support until well into 2012.
That leaves a lot of demand for a fire-breather, and it isn't being met. Rick Santorum or Herman Cain might catch fire, I suppose. But it sure looks wide open for Michelle Bachmann. If she can just keep a lid on her crazy side, she has enough high-profile support to avoid the kind of marginalization that Trump endured when the party elite ganged up on him. (Rush Limbaugh likes her, for instance.) Bachmann raises a ton of money, has a close relationship with Sarah Palin -- who still commands significant loyalty within the party but appears unlikely to run -- and has a real chance to win in Iowa.
Anyway, lots can happen, etc., but I see a real opening for Bachmann.