From leadership to openness. Is it any wonder that Connecticut, like so many states, is practically broke? Even the leadership doesn’t believe in leadership anymore. In “The United States of Ambition” (309 pages. Times. $23), Alan Ehrenhalt, executive editor of Governing magazine, provides a bracing and original explanation of how American politics has soured in the last 20 years. His focus is not on issues or voters but on the bright, ambitious men and women who replaced the part-timers and made polities their profession. Their very virtues–openness, independence, responsiveness–have handcuffed them in coming to grips with solutions to the country’s worsening problems.

“The irony of pursuing office in the 1990s is that one may reach a position of influence, find no established elite or power structure blocking its exercise, yet discover it more difficult than ever to lead,” Ehrenhalt writes. “We have replaced governments that could say yes-and make it stick-with governments that offer a multitude of interests the right to say no.”

The book’s first line is: “Who sent these people?” The answer is that they sent themselves. Ehrenhalt describes a world of “self-nomination,” where people decide to run for office as if they were starting a business. Like Fuller Brush men, they must enjoy door-to-door retail sales. If they don’t, politics is increasingly closed off to them. Every four years the complaint arises that the United States has needlessly limited the field of future presidents to those willing to endure the indignities of the process (groveling for money, speaking in sound bites). But Ehrenhalt shows that this is now true all throughout American politics, down to the campaign for city council in Concord, Calif.

Ehrenhalt’s analysis also explains why Democrats so greatly outnumber Republicans at every level of politics below president. The answer isn’t that Americans prefer divided government, or that unfair apportionment has robbed the GOP, or that voters are more liberal on local issues. It’s that Democrats fit the profile of the political professional more than Republicans do. Public service is usually less of a financial sacrifice for Democrats, who are making the transition from, say, teaching instead of business. And there’s a simple but often overlooked philosophical explanation. “The Republicans hate government,” says David Helbach, Democratic majority leader of the Wisconsin state Senate. “Why be here if you hate government? So they let us run it for them.” The result: the Democrats field more ambitious candidates, and the ones who want it most usually win.

Once ensconced in office, these political entrepreneurs regard defeat as something akin to bankruptcy. As “professionals,” their self-images are wrapped up in their jobs in ways that earlier generations of part-time mayors or legislators could never have imagined. This helps explain one of the most peculiar paradoxes in politics: the safer a seat, the more cowardly a legislator becomes. Voting against the interests of powerful constituents amounts to a form of professional suicide. In this sense, today’s politicians are often too responsive to the electorate. It sounds good when Jimmy Carter–or the disc jockey elected mayor of Sioux Falls, S.D.–comes to office owing almost nothing to anyone. But in practice it means that they have no one to rely on when it comes to the messy business of governing.

Ehrenhalt stops short of saying that he prefers Mayor Daley-style machine polities. Even if he did, it wouldn’t matter; the mediacracy is here to stay. But he asks, “Why is machine government a greater affront to democracy than a government of leaderless individuals prone to petty rivalry and endless bickering?” For a quarter century in Utica, N.Y., an unelected boss named Rufus Elefante ran city government from a booth at Marino’s restaurant. He was autocratic and tolerant of corruption, but the years following his demise have produced mostly talent-free leadership. Without some screening process-some political elite–the gears of government don’t work well.

Even when new politicians are bright and talented, their sense of their own professionalism makes them reluctant to defer. Why knock yourself out getting elected just to take a back seat to someone else? This mentality has been good for freshmen, who can make a splash, but bad for the institution as a whole. Leadership is impossible without some followership-some willingness to defer to power. “If you exhibit power, you scare the hell out of people,” says Loila Hunking, a former city commissioner in Sioux Falls. In that climate, deference is replaced by deferral–of problems.

The Connecticut Legislature was in crisis last week, paralyzed by its budget mess. Shaun McNally and his colleagues might learn from Alan Ehrenhalt that without real authority, nothing real gets authored, and the political system the country depends on slides into dangerous irrelevance.