The political predicate for this effort was straightforward: there was a large swath of the electorate in the ideological center — neither ardently conservative nor staunchly liberal — that could rally under the flag of a new, principled moderation. And there were elected officials in both parties that could sometimes coalesce around policies that advanced that flag. It was not easy; many fights broke along partisan lines. But not all: The center was strong enough to balance the budget, reform welfare, reduce crime, invest in education and research, and build a new architecture for the global economy.

Many Americans are nostalgic for the Clinton years. But we cannot return to them. Not only have our economy and society changed; so has the nature of the political challenge. During the past decade, the political polarization that began in the late 1960s has accelerated. The center has all but disappeared in the Congress, and it is weaker among the people as well. The Republican party is more homogeneously conservative than ever before, and liberals, though less dominant, are in the ascendency among Democrats. The result — a political system that cannot even conduct routine business, let along come to grips with the deeper challenges we confront.

As we lurch from crisis to crisis, the people are losing what little trust in government that they had managed to retain, and the rest of the world increasingly wonders about our capacity to govern ourselves and discharge the global responsibilities we have long shouldered.