Congress is dominated by intellectual lightweights who are chiefly consumed by electioneering and largely irrelevant in a body where a handful of members and many more staff do the actual work of legislating. And the business of the institution barely gets done because of a pernicious convergence of big money and consuming partisanship.

That is Robert Kaiser's unsparing assessment in "Act of Congress," the latest volume in a growing body of work lamenting our broken capital. The book is ostensibly about the 2010 Dodd-Frank financial-regulation bill. But, as Mr. Kaiser makes clear in his subtitle, Dodd-Frank is merely a vehicle for showing "how America's essential institution works, and how it doesn't."

Mr. Kaiser, a 50-year veteran of the Washington Post, secured the cooperation of the bill's namesakes, former Connecticut Sen. Chris Dodd and former Massachusetts Rep. Barney Frank, as well as that of their closest aides. (Mr. Dodd chaired the Senate Banking Committee, Mr. Frank the House Financial Services Committee.) "Act of Congress" thus offers a detailed "tick-tock," taking the reader through the bill's origins and drafting as well as the unsightly process by which it became law.

What makes "Act of Congress" a somewhat surprising addition to the Broken Congress genre is that Dodd-Frank would seem to be an example of the system working: Politicians responded to the perceived needs of their constituents, and a bill was passed. Yet, Mr. Kaiser argues, the process itself illustrated what's wrong with Washington, and the legislation ultimately passed more because of luck and circumstance than the wisdom of judicious lawmakers.

Mr. Kaiser depicts the gruesome business of legislating in the wickedly honest fashion only a journalistic veteran, liberated from the restraints imposed on daily reporters, could get away with. Messrs. Dodd and Frank had to fend off the big banks looking to avoid new regulations on one side and liberals pushing for unattainable new rules on the other. Hoping to keep the African-American members of his committee on board, Mr. Frank at one point summoned Goldman Sachs CEO Lloyd Blankfein to Washington to see if the banker could help restructure some debt that the country's largest minority-owned broadcasting company owed to Goldman. Mr. Frank, who is his otherwise voluble self throughout the book, sheepishly told Mr. Kaiser that he "never got into anything specific" with Mr. Blankfein.