Hillary Clinton and Donald Trump are the two most unpopular presidential candidates in modern American history.

But the despair and lack of control the public feels goes well beyond those two people. That despair is based on the sense that the political process no longer works.

Yuval Levin, the author of the recent book, “The Fractured Republic: Renewing America’s Social Contract in the Age of Individualism,” explains why we have come to this point and what needs to be done to make the process work again.

You should read it for three reasons. First, it will annoy and even threaten both conservatives and liberals. Second, the issues he raises will be important after the 2016 election, no matter who wins. Finally, if it has the same effect on you that it had on me, it can be a powerful reminder to re-examine your own views.

Levin is a conservative who, as he admits, sees the world through that lens. But he is able to transcend this. He offers much more than the typical right-wing criticisms and bromides and in fact is as critical, in some very original ways, of conservatives as he is of liberals.

To begin to understand Levin’s views, don’t think about politics at all. Think about a conversation you’ve probably had with some old guy who likes to go on and on about how much better the good old days were.

You know: “Those doggone computer games, in our days my pop would get out the Monopoly board and the family, God bless ’em, would …”

After a while you get tired out hearing it. “Hey, uncle, times change. Can’t go back, you know.”

According to Levin, both conservatives and liberals are still playing Parcheesi in a “Pokemon Go” world. Except that the consequences of this political nostalgia are far worse.

This political problem begins with dueling visions. The right and the left each have very different golden ages. 

For conservatives it is the early days of the Reagan administration when capitalism was freed up to do its good work and cultural diversity was still manageable: 1981. Uncle Ron.

The progressive golden age is those prosperous post-World War II years when blue collar jobs were stable and plentiful, inequality decreased, and, thanks to the civil rights movement, minorities began to progress in ways they never had before: 1965. Uncle Lyndon.

To the question, “How do we make things better?” Both Uncle Ron and Uncle Lyndon answers begin with “by going back to …” and then go off in totally different directions.

The plight of the unemployed is a good example. These duels lead debates framed as economic inequality (1965) versus cultural disintegration (1981), as if it is one or the other rather than a combination of both.

Levin says that each of these dueling nostalgias is irrelevant. Society is is far more pluralistic, chaotic, individualistic and “diffuse” than it was in 1965.

Well-being is about having money in your pocket as well a place to spend it that is a flourishing community made up of very diverse people who stress their commonality rather than their differences.

We no longer have anything close to the rough but powerful moral consensus that existed during those post-war years. And our economy does not work in ways consistent with either the liberal 1965 or conservative 1981 vision.

As a result, both conservatives and progressives have to move on.

The left, Levin says, needs to move on by reducing its emphasis on the federal government and return to its earlier powerful tradition of grassroots local politics.

Many progressives will disagree but won’t be surprised. Reaganites will also not be surprised by Levin’s views of capitalism’s strengths and weaknesses.

On the other hand, social conservatives are likely to feel more surprised and threatened.

The lack of moral consensus, he says, is a given. Diversity is the new normal that cannot be changed by passing laws trying to suppress it.

Levin tells social conservatives to quit feeling so beleaguered and martyred and get on with their lives. They cannot act as if they are the defenders of society’s virtues because that will not work.

Quit this nostalgia with its stress on what’s being lost and live your own life in a way that makes you happy and models your view of virtue to others.

Show others why your kind of virtuous life is worth living by doing good work with your family, your neighbors, schools and your community. That’s dramatically different from the typical social conservative response to a hot-button issue like same-sex marriage or Obamacare religious exemptions.

Imagine a liberal giving this advice to someone opposing same-sex marriage. The difference is that Levin has traditional conservative street cred.

Levin’s advice to social conservatives is consistent with his belief about the importance of community work and of strengthening the institutions closest to our everyday lives.

Levin is right about the importance of localism. Gridlock is likely to continue regardless of who becomes president. Like it or not, progressives will have to look elsewhere for political openings. 

In recent years, progressives have done that precisely because they saw no chance of success with Congress. Progressives led the successful fight for changes in state minimum wage laws.

The language of the Bernie Sanders campaign focused on federal government intervention, but as one commentator encouraging conservatives to feel the Bern said recently, “The Sanders revolution is primarily about something prior to the issues. It’s about democracy and civic engagement.”

What Levin tells social conservatives is really a broader message: Civic life is too important to be burdened by the politics of dueling nostalgias.

I read the book through a liberal lens because that’s what I am. So not surprisingly, I have some quarrels, especially with his views of capitalism.

It’s the book’s implicit overall message that I found most powerful because it is a caution against my own conventional thinking. That message is this: Celebrating diversity should be an important part of progressive politics, but diversity is not an end in itself.

The virtuous life involves more than prohibitions and preaching. 

Well-being is about having money in your pocket as well a place to spend it that is a flourishing community made up of very diverse people who stress their commonality rather than their differences.