This, from his home page, appears to be the thesis:
“Presidents can pretty easily pass tax cuts for the wealthy and powerful corporations. They can start whatever wars they wish and wiretap whomever they want without warrants. They can order the torture of terrorist suspects, lie about it and see that their intelligence services destroy the evidence. But what they cannot do, even with supermajorities in both houses of Congress behind them, is pass the kind of transformative progressive legislation that Barack Obama promised in his 2008 campaign.”
In addition to analysis, there are proposals:
Alterman offers a clear game plan for potential change, expounding his belief that “with regard to almost every single one of our problems, we need better, smarter organizing at every level and a willingness on the part of liberals and leftists to work with what remains of the center to begin the process of reforms that are a beginning, rather than an endpoint in the process of societal transformation.”
The book description also says that this is a "revised, updated, and much-expanded version of Alterman’s July 2010 online essay for The Nation." That essay lives here.
Click the pic to go to the book's page on Amazon.