We no longer have a leadership class — of the sort that existed as late as the Truman and Eisenhower administrations — that believes that governing means finding an equilibrium between different economic interests and a balance between political factions. Instead, we have the politics of solipsism. The political culture encourages politicians and activists to imagine that the country’s problems would be solved if other people’s interests and values magically disappeared.

The democratic triumph has created a nation that runs up huge debt and is increasingly incapable of finding a balance between competing interests. Today, the country faces three intertwined economic challenges. We have to make the welfare state fiscally sustainable. We have to do it in a way that preserves the economic dynamism in the country — that provides incentives for creative destruction. We also have to do it in a way that preserves social cohesion — that reduces the growing economic and lifestyle gaps between the educated and less educated.

These three goals are in tension with one another, but to prosper America has to address all three at the same time.

Voters will have to embrace institutional arrangements that restrain their desire to spend on themselves right now. Political leaders will have to find ways to moderate solipsistic tribalism and come up with tax and welfare state reforms that balance economic dynamism and social cohesion.

Over the past months, there has been some progress in getting Americans to accept the need for self-restraint. With their various budget approaches, the Simpson-Bowles commission, Paul Ryan and President Obama have sent the message that politics can no longer be about satisfying voters’ immediate needs. The public hasn’t bought it yet, but progress is being made.

There has been less progress in getting political leaders to come up with compromises that balance dynamism and cohesion. Republicans still mostly talk about incentives for growth, and Democrats still mostly talk about economic security. The breakthrough, if there is one, will come from the least directly democratic parts of the government, from the Senate or some commission of Establishment bigwigs. It will be enacted when voters realize we need to build arrangements to protect ourselves from our own weaknesses. It will all depend on reviving the republican virtues upon which the country was founded.