There’s no shortage of reasons why Democrats in the United States might feel demoralized. The party is shut out of power in the White House and Congress, and its hold on state legislatures is at the weakest point in decades.

Despite, or perhaps because, of those circumstances, Ruy Teixeira, a senior fellow at the left-leaning think tank the Center for American Progress, wants liberals to embrace optimism. In a new book, The Optimistic Leftist: Why the 21st Century Will Be Better Than You Think, he argues that liberal conventional wisdom—which he describes as marked by beliefs like “the left is weak” and the planet is “sliding inexorably toward catastrophe” in the face of threats like climate change—is not only deeply pessimistic, but also mistaken.

In the short-term, Teixeira believes the president and Republicans in Congress will have a hard time delivering on their promises, either because of voter pushback or because some, like reviving a coal industry hurt more by market forces than government regulation, won’t be possible to fulfill.

The Optimistic Leftist also makes the case that even developments that currently look like setbacks for the progressive movement are bound up in long-term trends that ultimately advantage liberals. Take Trump’s election. Teixeira argues that Trump’s campaign for infrastructure investment without regard to deficit reduction signals “the beginning of the end for austerity economics, formerly the linchpin of conservative policy.” And he sees the Democratic Party’s loss of white-working class voters as a manifestation of economic and social changes, including a transition away from  manufacturing, that are “powering the emergence of new left coalitions” that will strengthen the political left.

The Optimistic Leftist builds on The Emerging Democratic Majority, a book Teixeira co-authored with journalist John Judis in 2002, which argued that increasing demographic diversity would create an enduring advantage for Democrats in the United States. The Emerging Democratic Majority has been held up as a cautionary tale in making sweeping political predictions. But Teixeira argues that it has been oversimplified and misunderstood, saying in an interview that "it was not an argument that demographic change guarantees electoral success," but rather that demographic shifts create favorable political terrain for Democrats if they can find a way to make the most of it.

Part of the message of The Optimistic Leftist seems to be that underlying advantages aren’t enough to deliver political victory if liberals succumb to complacency or are paralyzed by fear. The book emphasizes that optimism about the future of the political left is not only warranted, but also strategic. An optimistic outlook will help liberals enact their political agenda and win elections, Teixeira believes, while wallowing in pessimism will hurt the progressive cause.

I recently spoke with Teixeira about those arguments, and their potential limitations. A transcript of our conversation, lightly edited for clarity and length, appears below.

Clare Foran: Your book argues that pessimism “dramatically undermines the appeal of the left,” and “does not motivate the typical person” while “optimism, by contrast, mobilizes people.” Why do you think pessimism won’t mobilize Democrats? Reporting on town hall protests that have taken place in the aftermath of the presidential election suggests that people are motivated by anger and fear, and that many had not engaged in political activism previously. Doesn’t that cut against your claim that optimism is a better motivator than pessimism?

Ruy Teixeira: Outrage can be powerful, but I think there’s a difference between bursts of protest driven by anger, and long-term movement building. Fear and anger can motivate people to show up and protest, but that could lead to burnout if political situation they are protesting doesn’t change the way they want it to overnight. Anger is ultimately demoralizing. If you want to sustain a political movement over the long-term then optimism is essential. It’s what will keep people from throwing up their hands and giving up.

Foran: Hillary Clinton may have failed to win over voters in the industrial midwest and the rust belt because she ran on a platform that suggested the status quo was working for America at a time when, as you note in your book, inequality has been rising for decades. What if an optimistic mentality hurts Democrats by alienating people who don’t feel optimistic about their own future?

Teixeira: I don’t think that Clinton’s problem, in terms of what caused her to lose the white working class, was that she was overly optimistic so much as that it was that she didn’t talk to these people, and didn’t act like she thought they were important. Nobody wants to be told they’re deplorable. You want to tell people that you understand your problems, and have a plan to help make life better. She actually had some great ideas about how people that live in those areas could be helped, but I don’t think she really conveyed that. I think Clinton thought she could basically get elected on the basis of “I’m not him,” without spending enough time making an optimistic case, and showing people she could deliver on that. That didn’t work.

Foran: Does that mean you don’t think the Democratic Party needs to re-think its policy agenda in the wake of the election loss? Shouldn’t the party be willing to engage in self-reflection right now, including asking hard questions like whether its platform actually appeals to voters?

Teixeira: I definitely think the Democrats need to engage in considerable self-reflection on their policy agenda. Clinton had some good policies for declining communities that, as I say, were not heard by some of the voters she lost, but it is also true that these policies needed to be more fleshed out than they were in her campaign. Making the woes of declining communities a central concern will not only change who hears these policies but also the content of these policies. In short, the Democrats need to make a big offer in this area and that will take a great deal of serious rethinking and hard work.

Foran: What do you make of the fact that Clinton won roughly three million more votes than Trump in the popular vote, while losing the Electoral College? Doesn’t that show that even if there is a liberal majority of voters, that isn’t enough to actually hold onto political power?

Teixeira: In The Emerging Democratic Majority, I think we correctly diagnosed how the overall country is changing, and how some states were likely to change, but I think we didn’t pay enough attention to some of the structural obstacles that Democrats must now confront, including the concentration of Democratic-leaning voters in urban areas, and how that might interact with gerrymandering. Those dynamics have turned out to be quite important. The lesson I take from that is that the left needs to be more competitive in a lot of places and can’t just rely on changing demographics. Democrats need to get into a position where they can de-gerrymander congressional districts, and to get to that point the party will need to be more competitive in parts of the country that aren’t necessarily liberal-leaning. They cannot just cede that to the Republican Party.

Foran: You note that many people on the left believe the outlook for the future is extremely bleak and that it may already be too late to solve problems like climate change. Why are you confident that’s not the case, and why do you think that mindset is detrimental?

Teixeira: I think a lot of people on the left have lost faith not only in the future, but in the ability of science, technology and people to create a better life for themselves in the future. One example is global warming. Many liberals believe we’re already doomed. I just think that’s not true, and at the very least that kind of mentality will not help us confront the problem. Clean energy is becoming much cheaper, but we need to find ways to accelerate its deployment. And if you take the view that the planet is doomed, that strikes fear into people’s hearts, makes them want to curl up in a ball on the couch and scream.

Foran: If, as you suggest, the left has lost faith in science and technology, why do you think that is?

Teixeira: I think that Democrats have faith in the conclusions of science, but have lost faith in the ability of science and technology to create a better future. There’s a sense that there’s a dark side to science. There are parts of the left that are worried about things like genetically-modified agriculture, for example. And I think global warming has contributed since there’s this idea that our own technological achievements have come back to haunt us by polluting the Earth. I think that has infected the way some people on the left think about the future of the United States and the world. But that risks downplaying all the benefits that science and technology have already delivered and will continue to deliver.  We shouldn’t lose sight of that.