Princeton, N.J. ? Appropriately enough, the title of the conference held here recently included a question mark: “The Polarization of American Politics: Myth or Reality?”

The 45 academics, politicians and journalists who gathered at Princeton’s Center for the Study of Democratic Politics never reached a vote, but all the evidence pointed toward the second alternative.

It quickly became clear that there is nothing new or unusual about the pattern of sharp partisanship shown in the last two presidential elections and in the frequent battles on Capitol Hill. David Brady of Stanford made the point that the late 19th century and parts of the 20th century were also times of party warfare; the anomaly was the relative truce for roughly 25 years after World War II.

David Rohde of Michigan State illustrated the point with a chart vividly showing how mid-20th century Congresses had seen significant overlap in the voting patterns of House Republicans and Democrats, whereas in today’s House, Democrats are clustered on the left of the ideological spectrum and Republicans on the right — with virtually no dissenters in between.

Despite some evidence that Americans en masse are not wildly antagonistic to each other’s views on social issues, John Evans of the University of California, San Diego, said that where differences existed, they tended to fall along party lines. James Gimpel of the University of Maryland and Bill Bishop of the Austin (Texas) American-Statesman showed that “red” and “blue” voters are increasingly living in separate enclaves, with distinctive lifestyles, attitudes and partisan leanings shared among neighbors.

To that extent, most of the conferees agreed, polarization is not just a phenomenon affecting politicians but something rooted in deeper social changes. Especially as sophisticated line-drawing for new congressional districts combines with the emerging pattern of like-minded voters living in geographical clusters, the latent divisions in American culture are made explicit on Election Day.

And then, many conferees said, those differences are sharpened by several forces operating independently in and on the political system. Television advertising, as Diana Mutz of the University of Pennsylvania demonstrated, inflames viewers’ emotions and decreases their ability to remember or accept as legitimate opposing arguments. In today’s multifaceted media world, Jonathan Alter of Newsweek said, people easily find reinforcement for their own political preferences by choosing the channels they watch or the publications they read.

Inside Congress, Rohde said, the increasing homogeneity within each party has made members willing to give more power to their leaders. What began on the Democratic side with former Speaker Jim Wright was carried even further by Newt Gingrich, when the Republicans took over, and it continues now with Dennis Hastert and Tom DeLay.

But as John Pitney of Claremont McKenna College pointed out, that has led to a “new game of defeat the leader” on both sides of the Capitol. The victims in the past decade include Tom Foley and Gingrich, Tony Coelho, Bob Livingston, Trent Lott and, most recently, Tom Daschle. Their downfall — whether the result of more intensive (and negative) media scrutiny, tougher ethics rules or the nationalization of local election races — symbolizes and reinforces the increasing polarization in Congress.

Barbara Sinclair of UCLA said that as a result, the opportunities and the constraints for individual members of Congress have changed significantly. In the House, lawmakers’ views are heeded inside party caucuses, as witness Hastert’s initial decision three weeks ago to hold off a vote on the intelligence system reform bill after he ran into strenuous opposition at a closed-door Republican conference. But members who go outside the party to make deals can be punished.

Although the Senate is less overtly partisan than the House, Republican Sen. Arlen Specter of Pennsylvania, who sometimes has voted with the Democrats on economic or social issues, was threatened by party leaders with the loss of his claim to the Judiciary Committee chairmanship until he gave them assurances he would be more cooperative.

The members of Congress who joined in the conference confirmed most of these observations, but differed sharply — on partisan lines — about the consequences. Democratic Rep. David Price of North Carolina argued that party discipline enforced by Republican leaders has “gone beyond its proper bounds,” leaving Democrats too often shut out of the legislative process. Republican Rep. Tom Cole of Oklahoma countered that the virtual disappearance of conservative Southern Democrats from Congress has left the Republicans with few potential partners for bipartisan legislation.

Cole said the closeness of margins had reinforced the need for party discipline, adding. “The determination of this generation of Republican leaders not to go back to minority status must not be underestimated.”

Meaning, I think, that polarization will be around for quite a while.

— David Broder is a columnist for Washington Post Writers Group.