Julian E. Zelizer: Four new Kings on the Hill in Washington
Last month, Sen. Sherrod Brown of Ohio, a strong defender of the public option for health care, warned: "I don't want four Democratic senators dictating to the other 56 of us and to the country, when the public option has this much support, that it is not going to be in it."
But in the end, those senators won the battle over the public option, as well as several other provisions in the health care bill.
They have emerged as the powerhouses of the Senate.
Before 2009, most Americans never heard of Sens. Ben Nelson, Max Baucus or Kent Conrad. More have heard of the Independent Sen. Joe Lieberman as a result of his Democratic vice presidential bid in 2000.
Yet now they are the movers and shakers in the Senate. Anyone who follows politics knows exactly who they are. It could not be further from 2005 when Nicholas Confessore in The New York Times wrote that "centrist Democrats today struggle with an unfriendly environment."
Throughout the Senate debate over health care, the centrists repeatedly forced the president's hand by insisting on changes to the legislation that made Obama's liberal base furious and which will constrain the impact of this legislation. Health care was the second major victory for centrists this year. They also were able to cut down the size of the economic stimulus bill back in February 2008.
Why is this small group of senators so influential and will this change? The first reason has to do with the nature of the Democratic Party. Democrats have never been as ideologically disciplined as the Republicans, and they have been less successful containing party differences.
Moreover, since 2006, Democratic leaders embraced a campaign strategy of attempting to expand their numbers by encroaching into conservative districts and states: The 50-state strategy.
In 2006 and 2008, the strategy paid off. The cost, however, has been that President Obama needs to maintain support among legislators who come from areas that don't lean Democratic -- or who don't share his policy views.
When some Democrats pushed to punish Lieberman -- who supported Arizona Sen. John McCain in the 2008 presidential campaign -- by stripping him of his committee chairmanship, Obama refused and insisted on keeping him in the Democratic coalition.
The second factor behind the new kings of the hill has to do with the sharpening of the partisan divide on Capitol Hill. The impact of growing party polarization since the 1970s has meant that winning votes from the other party is extraordinarily difficult. Except for rare moments, neither party can count on winning significant blocks of votes from the other side of the aisle.
As a result, it is essential that the majority party remains relatively unified in order to pass legislation. Obama has learned this lesson well. With health care in the Senate, he even failed to win the vote of the moderate Republicans Susan Collins and Olympia Snowe. Because of such partisan intensity, the vote of just a few Democrats becomes that much more important. Nor can he afford to lose the vote of a defiant Independent, Lieberman, who still goes along with Democrats on many votes.
Finally, institutions matter. The U.S. now has a Senate that operates as a supermajority. The Senate now requires 60 votes on any piece of legislation given that senators are willing to use the filibuster on almost any bill. If the majority party needs 60 votes to pass a bill, and it can't win votes from the other side, a handful of moderates wield tremendous power.
[Excerpt - Continue reading on CNN.com]