In December 2022, early into what he now describes as his political journey, Senator Chris Murphy of Connecticut gave a speech warning his fellow Democrats that they were ignoring a crisis staring them in the face.

For over a year, President Biden and his allies had been promoting data showing an economic miracle, as friendly pundits described it — a record-setting stock market, low unemployment and G.D.P. growth outpacing that of almost every other Western nation. But very few voters believed the story those metrics were telling. In poll after poll, they expressed a bleak view of the economy — to the frustration of both Democrats and many economists.

Mr. Murphy thought he knew why. “The challenges America faces aren’t really logistical,” he told the crowd. “They are metaphysical. And the sooner we understand the unspooling of identity and meaning that is happening in America today, the sooner we can come up with practical policies to address this crisis.”

The subject of the speech was what Mr. Murphy called the imminent “fall of American neoliberalism.” This may sound like strange talk from a middle-of-the-road Democratic senator, who up until that point had never seemed to believe that the system that orders our world was on the verge of falling. He campaigned for Hillary Clinton against Bernie Sanders during the 2016 primaries, and his most visible political stance up until then was his work on gun control after the Sandy Hook shooting.

Thoughtful but prone to speaking in talking points, he still comes off more like a polished Connecticut dad than a champion of the disaffected. But Mr. Murphy was then in the full flush of discovering a new way of understanding the state of the nation, and it had set him on a journey that even he has struggled sometimes to describe: to understand how the version of liberalism we’d adopted — defined by its emphasis on free markets, globalization and consumer choice — had begun to feel to many like a dead end and to come up with a new vision for the Democratic Party.

As the Democrats gather for their national convention this week, with Kamala Harris as their candidate for president, the party has a long way to go toward confronting the crisis Mr. Murphy sees.

America’s leaders — from both parties — have long been guided by what’s often called the neoliberal consensus: the idea that “barrier-free international markets, rapidly advancing communications technology and automation, decreased regulation and empowered citizen-consumers would be the keys to prosperity, happiness and strong democracy,” as Mr. Murphy put it. More simply, it’s a shared assumption that what’s good for markets is good for society.

This assumption shapes our politics so deeply that it’s almost invisible. But the idea that modern life is a story of constant economic and technological progress steadily making the world a better place has stopped lining up with how Americans feel. You can look at statistics about suicide, depression, overdoses and declining life expectancy. You can point to the fact that roughly 70 percent of wild animals on Earth have disappeared since 1970 or examine the astonishingly pervasive sense of loneliness that now seems to color so many American lives. But no statistics really capture the feeling, shared by growing numbers of Americans, that the world is just getting worse.

It’s a “metaphysical” problem, as Mr. Murphy put it. And he began to think that the economic metrics used by economists and presidents to capture the state of the nation were masking a vast “spiritual crisis.”

He didn’t know it then, but he was homing in on a problem that Democrats have yet to figure out how to address. Donald Trump and the movement around him have tapped into a sense of deep alienation and national malaise. Democrats often have trouble even acknowledging those feelings are real.

In the final days of his campaign, even as he began to push a raft of economically populist plans, Mr. Biden told ABC, “I don’t think America is in tough shape.”

No one, Mr. Murphy included, expected Mr. Biden to talk about a metaphysical crisis facing the nation he governed. In an age when elections seem to run full time, an incumbent president has little choice but to argue that things are great and getting better. But now that Ms. Harris is their nominee, the Democrats have a choice: They can continue to argue that the true danger is Mr. Trump and that we need only shore up our institutions against the threat he poses, or they can push her to speak for the almost 70 percent of Americans who said that they want to see fundamental changes to our political and economic systems or even to see them torn down entirely.

So far, Ms. Harris has been vague even on relatively basic policy plans and has offered no hint of a vision for how to remake an order that very few people today believe is working, much less on deeper questions about how to rebuild our shredded social fabric.

Mr. Murphy is a team player and has publicly been fully supportive of Ms. Harris, but he also wants Democrats to squarely acknowledge the crisis he believes the country is facing and to offer a vision to unmake the “massive concentration of corporate power” that he thinks is the source of these feelings of helplessness and hopelessness. Only by offering a “firm break” with the past, he believes, can Democrats compete with Republicans like JD Vance, who, with outlines like Project 2025, have a plan to remake American statecraft in their image and who are campaigning on a decisive break with the status quo.

Academics, think tanks and magazines are buzzing with conversations about how to undo the damage wrought by half a century of misguided economic policies. On the right, that debate has already spilled out into the public view. But on the center-left, at least, very few politicians seem to be aware of this conversation — or at least willing to talk about it in front of voters.

Mr. Murphy has been warning for years that by failing to offer a clear vision of the future, Democrats risk losing to a “postdemocracy” Republican Party that might rig the electoral system “in order to make sure Democrats never win again.” His warnings may sound out of place with the sudden mood shift in the party over the past few weeks. But behind the scenes, he is far from the only Democrat raising these concerns. Just a few days before the convention, Mr. Murphy’s good friend Ben Rhodes, a former senior adviser to Barack Obama, told me that in the age of Mr. Trump, Democrats have found themselves in a “trap”: How can they present themselves as the party of fundamental change when they spent the past eight years arguing that America’s institutions need to be shored up against the urgent threat of Trumpism?

“Can you reform that system so much that it ceases to be that and starts to be something else?” Mr. Rhodes asked me. “Or does it have to be blown up?” Many on the center-left worry that, absent a liberal vision for how this reform may work, Americans will opt to blow things up.

Without much fanfare, the Biden administration has already embraced many of the policies Mr. Murphy is calling for: industrial policy, tariffs, a campaign against corporate monopolies. His vision of economic nationalism can look very similar to the one offered by “America First” Republicans, but the specifics reveal very different priorities; Mr. Murphy supports far higher levels of immigration and paid family leave over the child tax credits increasingly favored by conservatives — some of whom see paid family leave as an unfair subsidy favoring working mothers over those who choose to stay at home to raise kids.

But they have a common goal: to remake the incentive structure of our economy. “The core issue is that our economy became one based on extracting rents,” Mr. Krein told me, “rather than building things.” It rewards those who invent clever ways to squeeze money out of government and regular people. This is the simple explanation for why so many jobs feel soulless and so many Americans feel harried and troubled amid the vast material wealth our country produces.

“That’s what people are really complaining about when they talk about neoliberalism,” Mr. Krein said. “But that’s tough to fit on a bumper sticker.”

“Great leaders tell stories that fit within the cultural and religious contexts of nations,” the Bay Area representative Ro Khanna told me. He helped write the CHIPS and Science Act, but he thought that the Democrats had failed to explain what they wanted it to achieve. “Symbolically, politically and culturally, Biden announcing three new steel plants in Pennsylvania, Michigan and Ohio might have done more than the entire CHIPs act combined, because it would have showed that we were listening,” Mr. Krein said.

“Politics is not just about policy,” he said. “It’s about the vision of a nation. It’s about signaling that we’re heading somewhere.”

If the selection of Mr. Vance as their vice-presidential nominee is any indication, Republicans are beginning to coalesce around a vision for the future. It begins with plans to fire thousands of civil servants in an attempt to unmake the so-called administrative state, which they believe promotes liberal values and has enveloped America in bureaucracy. They seek to pull back from the internationalist foreign policy and free-trade policies that have guided both parties for decades. They hope to increase America’s birthrate and cut immigration and may pursue steps like reducing the value of the dollar, which they argue would help American-produced goods compete in an international marketplace. “We’re going to build factories again, put people to work making real products for American families, made with the hands of American workers,” Mr. Vance said during his speech at the Republican National Convention.

Liberals view many of the plans with horror. But the party has struggled to offer a coherent politics to answer the discontent with globalization, the technological colonization of our minds and lives and the sense of disempowerment so many feel. “The common ground is in the critique,” Mr. Khanna said. “But there are still large areas of difference about where we want to go from here. I don’t think liberalism as it’s defined now is enough to get us there.”

Last summer, I attended a dinner hosted by Sohrab Ahmari, a co-founder of Compact, where a couple of dozen people got together to talk about how this future might take shape. It was held at an Italian restaurant in the East 50s of Manhattan and conducted under Chatham House rules, which meant that what was said and the names of people who attended were, like many conversations about new directions for the country among think tankers and politicos, off the record. But the people there represented a decent cross-section of American political views, from people keeping the Sanders-style left-wing populist faith to centrist civil servants to more or less avowed reactionaries.

All the attendees seemed to take for granted that the neoliberal era was nearing its endpoint — a fact notable only because it reflected a consensus that has still barely filtered into our mainstream political conversations. It would be very hard, these days, to put together a room of well-informed academics or policy types under the age of 70 who don’t think that America faces a choice between huge systemic reform and a full-blown crisis.

The problem, for any Democrat, is to find a way to turn this understanding into winning politics. When I called Steve Bannon, Mr. Trump’s onetime chief White House strategist, late last year, he was very clear that he didn’t think Mr. Murphy’s vision went far enough. Mr. Bannon has frequently praised Mr. Khanna — jocularly accusing him of stealing “our” ideas in his proposals to rebuild America’s manufacturing capacity. But Mr. Bannon was savagely and profanely dismissive of Mr. Murphy, suggesting that he was angling to run for president someday and, even after his political awakening, was still too cautious and naïve to confront the structural issues that shape our economy. “He has a very tough road ahead, and here’s why,” Mr. Bannon said. “There’s no audience for what he’s saying on the Democratic side. Democratic voters like the system.”

Mr. Bannon called Mr. Murphy a “neoliberal neocon,” a double epithet Mr. Bannon uses to dismiss politicians of both parties who he believes care more about maintaining America’s superpower status than they do about protecting the national interest. “He supports the war machine,” Mr. Bannon said.

Mr. Murphy has joined with both leftists and Bannon-friendly Republican isolationists in opposing American involvement in conflicts like the civil war in Yemen. But he remains mostly within the Democratic mainstream on foreign policy issues like helping to fund Ukraine and maintaining America’s traditional leading military role in the world. Unlike many on both the right and left, he has shown little desire to unmake the complex military and financial systems that critics on both sides often describe as the American Empire.

The trouble is that orienting the American economy back toward producing things and building a strong middle class may mean reassessing those old ideas and asking tough questions about whether we can afford to maintain our military might or continue financing the federal government with debt. These are now common talking points on the right, and at a time when Mr. Trump and his allies hint at ideas like withdrawing from NATO and curtailing the independence of the Federal Reserve, even a critic of the globalized economic order like Mr. Murphy can end up looking like a milquetoast defender of the status quo.

When I finally met Mr. Murphy in person, a year after he first emailed me, Mr. Ahmari had visited him the week before, and he was excitedly preparing to announce a new legislative collaboration with Mr. Vance. (Mr. Murphy’s staff later noted that the collaboration did not come to fruition.) At 51, he has an earnest seriousness of someone genuinely troubled, and a bit confounded, by the parlous state of the country.

I asked Mr. Murphy if I was right that his aim really was to unmake the neoliberal system as we knew it. “You are,” he said. He anticipated my next question, about whether it would ever be possible to translate this kind of big-picture conversation to mainstream politics. I mentioned that I’d seen brutal responses to his testing posts online. “I get a lot of pushback from the left, as you’ve seen,” he said, “and I get a lot of it privately as well.” There is a belief, he continued, “that the people who are against us are hardened by cultural and social and racial biases. And that a higher minimum wage is not going to convince them to align themselves with a group that thinks Black people should be empowered. I don’t know that I believe that.”

As if anticipating the Harris/Trump race, he described an electoral landscape where Democratic candidates who won a majority of the popular vote might still lose the presidency if they couldn’t win states in the Upper Midwest. “I think that our coalition is bound to lose if we don’t find a way to reach out to some element of the folks who have been hoodwinked by Donald Trump. We don’t have to win over 25 percent of his voters. We have to win 5 or 10 percent of his voters. I’m just fed up with the political people who say, ‘Why is this going to be bad for us, as the left?’ I’m engaged in a bigger project,” Mr. Murphy said. “I think that we are more likely to protect a woman’s right to choose if we win bigger majorities and expand our coalition a little bit by bringing in people who might occasionally disagree with us on social issues but prioritize our agreement on anti-neoliberalism issues.”

We went out for drinks that evening. The conversation got looser. A beer or two in, I asked him if, given the program of economic nationalism he’d proposed, he considered himself an American nationalist. He demurred. “But I do believe,” he said, “that we have to tell a story about what makes America different. To make people proud of being American. And make them believe that that identity is more important than their individual political identity.”

It was on some level a question that went to the heart of his project and the issue of how it differed from the plans emerging on the right. “We have to build a uniquely American economy,” he said. “We have to convince people that there is a uniquely American identity while understanding that there are still important moments where you have to engage the rest of the world. That’s not a bumper sticker.” He paused. “That’s what makes this project really hard.”