No More Moderates! No More Diversity!

David Gergen and Michael Zuckerman:

(CNN) — As this election season unfolds, we are watching an age-old dream in politics go horribly smash. It isn’t good for politics, and it sure isn’t good for the country.

President Franklin Roosevelt helped to fire up the dream during his second term in office. Coming off a massive landslide in 1936, he believed that it would be far better for governing if the Democrats became the liberal party and Republicans the conservative one. In the 1938 congressional elections, he barnstormed across the South trying to purge the Democratic Party of several incumbent conservatives. His efforts backfired — the incumbents won and were sore at FDR — but the dream became a staple of politics.

In 1950, for example, in one of the landmark studies in political science — one still read today by undergraduate majors — some of the best minds of the day argued strongly that the nation would benefit from more ideologically “coherent” parties: that things would be better if Democrats stood firmly for a liberal ideology and Republicans for a conservative one.

That way, people would have clear choices, they would know what they were voting for, and they could count on their party delivering if it were in power. “Shoo out those racially suspect Sunbelt conservatives from Democratic ranks and those lily-livered Northeastern liberals from the GOP. And maybe some of those moderates, too.” So the thinking went.

Well, in recent years, we have seen the dream come true. And guess what? It is producing a mess. As each of the parties has moved toward ideological purity, our politics have become ever more polarized, our governing ever more paralyzed. Extremists increasingly run the show….

As of 2010, there were as many as 54 Blue Dogs, but the midterms knocked their caucus down to 26. With retirements and primaries, that number will probably be well below 20 by next January — an effect that further turns Democrats into the party of the left.

Some activists — conservative Grover Norquist among them — argue that over time, this purification will be good for the U.S. But so far, the task of governing has gotten much tougher, and what little trust is left among the parties is evaporating. As the parties become more ideological, it’s easier to demonize the other side and harder to rationalize working with it — both to your colleagues and your constituents. Woe to be you in your next primary if you have consorted with the enemy.

Under heavy pressures for party conformity, legislation by nature becomes a more partisan undertaking. Hard to believe it now, but big programs like Medicare and Medicaid in the 1960s, or tax and Social Security reform in the 1980s, passed with broad bipartisan support.