It wasn’t so long ago that “epistemic closure” was supposedly the exclusive province of Republicans. For years, self-satisfied liberal analysts maintained that the Fox News Channel and talk radio had incepted a kind of mood disorder in the conservative body politic that refused all evidence or information challenging to its most deeply held beliefs. “Every intellectual movement needs to constantly question itself; otherwise it becomes stale,” wrote former-Republican-official-turned-GOP-critic Bruce Bartlett in a typical 2010 remark. “Conservatives have sort of reached a position of intellectual closure.”

Observers with no clear interest in the Republican Party’s well-being or the health of the conservative movement offered sorrowful aperçues about this disorder. In the wake of Mitt Romney’s 2012 loss, MSNBC host Rachel Maddow counseled conservatives and Republicans to “pop the factual bubble they have been so happy living inside if they do not want to get shellacked again.”

The Atlantic’s Marc Armbinder mourned as follows: “I want to find Republicans to take seriously, but it is hard.” That was not, he confessed, because the right’s more serious voices didn’t exist, but because “they are marginalized, even self-marginalizing.” The GOP, these ubiquitous liberal voices advised, would have to break its addiction to this self-reinforcing feedback loop if it was ever again going to be a nationally representative institution.

In 2019, the Democratic Party is giving signs of suffering from a form of epistemic closure of its own. After the 2010 midterm election brought Barack Obama’s aggressive legislative agenda to a halt, the party’s progressive wing has been in the political wilderness. The progressives spent most of the decade incubating a set of ambitious and far-reaching ideas—policies that never seem to have been examined along the way by a single skeptical eye. They have now emerged from their cocoon as the revivified Democratic Party has taken charge of the House of Representatives and readies itself for a 2020 challenge to Donald Trump. And the progressives who are besotted with them seem genuinely surprised that their policy preferences are being greeted with skepticism at best and astonishment at worst.

The emblematic policy is a smorgasbord of desiderata called the Green New Deal, only some of which is dedicated to environmental remediation. The Democratic Party’s climate catastrophists appear to have convinced themselves that the only surefire way to prevent runaway climate change is the radical transformation of the economy. To call this 10-year plan ambitious is an understatement. The initial proposal for a Green New Deal congressional subcommittee called for the shuttering of all fossil-fuel-generating power plants, replacing the country’s energy grid, enhancing its water-related infrastructure, upgrading “every residential and industrial building” in the United States, scaling back America’s industrial agriculture sector to “local-scale,” eliminating all greenhouse-gas emissions produced by transportation, and exporting this technological and paradigmatic revolution around the world.

This was no rough draft. Within weeks, more than 60 House Democrats co-sponsored a legislative resolution backing these measures. Democratic 2020 hopefuls including Elizabeth Warren, Kamala Harris, Kirsten Gillibrand, Cory Booker, Julian Castro, Pete Buttigieg, Tulsi Gabbard, and Amy Klobuchar have endorsed the Green New Deal, in whole or “in concept” as “aspirational.”

Given all this support, you might think that the kinks of this wild-eyed proposal were worked out long ago. You’d be wrong.

The Green New Deal’s chief proponent—Representative Alexandria Ocasio-Cortez—promoted the plan in a Frequently Asked Questions (FAQ) document published on her website. The FAQ explained that America would be reducing its fossil-fuel emissions to zero while eliminating nuclear-power generation, which would be beyond the capacity of existing technology to achieve in a 10-year time frame. The FAQ also said the Green New Deal would eventually retire the internal combustion engine. The document confessed that emissions from livestock and airplanes might not be eliminated entirely at the end of a decade, but we’d be well on our way. It would use “highspeed rail at a scale where air travel stops becoming necessary,” an implausible notion considering that even California’s progressive Governor Gavin Newsom couldn’t make a bullet train linking the Bay Area and Silicon Valley work at a reasonable cost. Indeed, the FAQ was disdainful of the notion that cost should be part of the equation. “The question isn’t how will we pay for it,” the FAQ insisted, “but what will we do with our new shared prosperity.”

The FAQ was a disaster. It was mocked, dismissed, and eventually scrubbed from the Internet. The Federalist’s David Harsanyi called it a manual for how to “tear down modernity.” The FAQ was “a recipe for economic Armageddon,” wrote the Washington Examiner’s Tom Rogan. In what may be the sincerest admission that Ocasio-Cortez had done her party no favors, the New York Times’ headline read, “Ocasio-Cortez Team Flubs a Green New Deal Summary, and Republicans Pounce.” But rather than fall on their swords and acknowledge the crudity of their rollout of the policy, Ocasio-Cortez’s advisers tried to convince observers that their eyes had deceived them. Robert Hockett, a Cornell law professor and adviser to Ocasio-Cortez, told Fox News Channel’s Tucker Carlson that the FAQ was a “doctored document that someone else has been circulating.” Her chief of staff, Saikat Chakrabarti, later claimed it was only one of many “early drafts” that “got leaked” to the press.

Once it was exposed to the sunlight, the Green New Deal instantly began to wilt. What would it do to help the millions of people who would be displaced amid the abolition of any occupation that is made possible by the burning of fossil fuels? Well, it commits the government to “guaranteeing a job” to “all people of the United States.” Ocasio-Cortez’s boosters were especially humiliated by a phrase in the FAQ that promised occupations to those who are “unwilling to work,” but the unwilling are surely part of a category as broad as literally everyone in America. To be sure, a federal jobs guarantee has been the great hope of the progressive left for generations, but it’s tough to generate traction for that kind of plan while at the same time outlawing most of the productive economy.

A Brookings Institution analysis of some of the leading proposals for a federal jobs program found that there are about 50 million Americans who could take advantage of such a program—some who are currently unemployed, but many more who are employed full- or part-time making less than $15 per hour. Such a program would have positive effects. The number of underemployed workers would collapse, poverty rates would decline, and wages would rise as competition for low-skill occupations increased.

But what kinds of work would this program guarantee? Some proposals would expand the ranks of teachers, teachers’ assistants, office-support professionals, personal-care providers, construction and maintenance workers, and police and security officers. But that would be little consolation for those employed in the millions of occupations that would be phased out by the Green New Deal, many of which require professional expertise accumulated over the course of a lifetime and provide competition commensurate with those skillsets. A petroleum engineer would not be fulfilled by his new position as a public safety officer making minimum wage.

The most aggressive jobs programs would require $5 trillion over ten years, according to Brookings. But that wouldn’t cover the costs associated with providing displaced Americans job training, educational resources, and access to a college degree. That, too, is in the Green New Deal, but it’s not new. “Free” college has become a staple part of the progressive platform.

Making a four-year college degree a “debt-free” proposition has become a feature of the Democratic pitch to voters, and few have put as much meat on its bones as Senator Bernie Sanders. His plan would cost the federal treasury $470 billion over 10 years, but the financial strain is the least of his proposal’s objectionable effects. Ironically, “free college” would exacerbate the very inequality he and other progressives claim to oppose.

Prior to 1998, the United Kingdom experimented with taxpayer-funded university education, but the scheme became untenable when more and more people began to seek degrees as demand for skilled labor increased. The effect of “free college” was social stratification. Qualified students sought out schools with the most resources, while lower-tier colleges stagnated as their incentives to innovate dried up. These perverse incentives disappeared when the U.K. introduced market reforms into the higher-education system. And contrary to progressives’ expectations, enrollment continues to rise.

We can already see the pernicious effects of “free college” on social mobility in states that have tried to make college “debt-free.” State-level programs that cover the cost of college after students take advantage of federal aid divert resources to middle-class students and away from poorer degree-seekers. Two studies, one from the Institute of Higher Education Policy and another conducted by Ed Trust, found that state-level “free-college” programs without restrictions provided less benefit to lower-income students and undergraduate students who are over 25 years old than they would receive from colleges outside the state where they reside.

“These students still cannot afford college because they struggle with non-tuition costs, such as books, housing, and transportation,” wrote Ed Trust senior higher-education policy analyst Katie Berger. This organization also found that the 200 “free college” programs in 41 states often limit eligibility based on GPA, credit accumulation, and residency. This helps manage costs but also has “a disproportionate impact on the students least served by higher education and fail[s] to address our nation’s college affordability problem.”

What’s more, states and municipalities struggling to comply with a federal higher-education mandate would face a widely expanded pool of applicants, forcing them to enlarge their unwieldy armies of non-faculty administrators. Between 1985 and 2005, the cost of a four-year degree exploded. In that same period, the number of faculty in higher education increased by only 50 percent while administrators increased by 85 percent and their staffs ballooned by a staggering 240 percent. Those administrative professionals are not performing make-work jobs. They’re navigating a complex labyrinth of federal regulations and performing managerial oversight that full-time faculty cannot. “Free college” would only exacerbate the conditions that have led college costs to increase by 500 percent in roughly those same two decades, which suggests that the estimated costs of Sanders’s proposal are on the low end.

For some Democrats, the promise of “economic security” would not be satisfied by the promise of employment and education. For them, “economic security” means a guaranteed income provided by the government that would, in one go, raise every American over the annual poverty threshold. While prominent Democratic lawmakers, including Hillary Clinton and Joe Biden, were sour on the idea only a few years ago, the Green New Deal subcommittee proposal endorses “basic income programs.” Goaded by tech-sector giants including Mark Zuckerberg, Elon Musk, and Richard Branson, the California Democratic Party has now embraced the idea of a “universal basic income.” Senators Kamala Harris and Cory Booker have also endorsed the concept of a “UBI.”

Ray Dalio, manager of the hedge fund Bridgewater Associates, estimated that providing every American with $12,000 per year—the current poverty threshold—would cost approximately $3.8 trillion every year. That is approximately 21 percent of GDP and about 78 percent of all tax revenues. If a price tag amounting to $38 trillion over 10 years doesn’t make you sweat, how about the fact that this old idea has been an objective failure everywhere it’s been tried?

Finland recently experimented with a program that provided 2,000 unemployed people with a basic income and no reporting requirements for two years. While the recipients experienced more happiness and less stress than the control group, the administrators found to their distress that the program members were not encouraged by their guaranteed income to go out and find a job. They simply lived off the pilot program’s per diem. What’s more, the Finnish government concluded that the program, applied to all its 5.5 million people, would require across-the-board income-tax hikes of nearly 30 percent. The nation discontinued the experiment. In July 2017, Ontario also experimented with a UBI and encountered many of the same problems as Finland.

This was all predictable, due to prior experience with the idea in…the United States. The “negative income tax,” as it was called, was essentially a minimum income that phased out as earnings increased. In 1968, the White House Office of Economic Opportunity selected a series of communities in New Jersey to test the NIT. The number of hours worked by the program’s beneficiaries declined, and those who lost a job while on this form of assistance took longer to find new work than did those without it.

What’s more, as the Stanford Research Institute (SRI) found, the experiment did not increase nuclear family cohesion, as theorists expected. Instead, it exacerbated the conditions that were leading families to come apart. “The SRI researchers,” the study read, “hypothesized that the availability of the income guarantee to some families reduced the pressure on the breadwinner to remain with the family, while the benefit-reduction rate also reduced the value to the family of keeping a wage earner in the unit.”

It goes without saying that there can be no “economic security” without the peace of mind provided by health-care coverage. Perhaps that’s why health-care mandates are also part of the Green New Deal, which—let us recall—is supposedly about fighting climate change. This is just one element of the Democratic Party’s embrace of ever more radical approaches to health insurance. After the end of the Obama presidency, the Obamacare plan was not only challenged programmatically by the Republicans who successfully sought to remove its mandate, but philosophically by Democrats pushing for a single-payer system. In 2017, one-third of the Democratic caucus in the Senate backed Bernie Sanders’s Medicare-for-all single-payer plan, and it has only become more popular in the years since. Today, more than half of the Democratic Party’s representatives in the House want to open Medicare up to all Americans. They regularly point to polling that suggests most voters are on their side. But that enthusiasm dissolves the minute Americans take a cursory glance under Medicare-for-all’s hood.

Presidential candidate Kamala Harris’s experience is illustrative. Shortly after launching her presidential bid, Harris sat down with CNN host Jake Tapper, who asked her about the provisions in the single-payer bill she co-sponsored that would all but do away with private insurance. “Let’s eliminate all that,” she said dismissively. “Let’s move on.”

The firestorm that followed these comments suggests that Harris hadn’t thoroughly gamed this out. “It would take a mighty transition to move from where we are to that,” said the number two Democrat in the Senate, Dick Durbin. Senator Tim Kaine added that he, too, would be uncomfortable forcing the 80 percent of Americans with employer-sponsored private insurance into a government program. “I’m not going to say you have to give it up,” he said. “You can’t just pull the rug out from underneath everybody’s feet,” Senator Gary Peters cautioned. Senator Chris Murphy advocated some form of health-care reform that would be “more politically palatable and ultimately more popular” than Harris’s “statutory prohibition private plans.” California Senator Dianne Feinstein said simply, “I’m not there yet.”

What we learned from this is that most Americans might not have known that expanding Medicare to all Americans essentially nationalizes the health-insurance industry. Sanders’s proposal makes employer-sponsored health insurance illegal and would likely crowd most other plans out of the marketplace by leaving them with an unsustainably small risk pool. That would force approximately 150 million Americans and their dependents into a government-sponsored insurance monopoly.

Every one of the 16 Senate Democrats who co-sponsored Sanders’s single-payer bill knew this, but Harris’s unwise acknowledgement prompted a Democratic stampede away from Medicare-for-all’s central plank. Many Senate Democrats balked at the idea that you could simply legislate a $900-billion-per-year industry out of existence overnight. Fellow presidential candidate Cory Booker, who also co-sponsored Sanders’s bill, went wobbly. “Even countries that have vast access to publicly offered health care still have private health care,” he said when asked if he, too, wanted to eliminate private insurance. “So, no.” With the pressure on, Harris relented. Her advisers confessed that the senator was suddenly amenable to health-care reform plans short of single-payer.

Once again, this progressive idea that gained such purchase among Democrats blew up on the tarmac the first time it met an even mildly skeptical audience. And the nationalization of the health-insurance industry was only the most obvious of Sanders-style single-payer’s drawbacks. Two independent analyses of his plan pegged its costs at around $32 trillion over 10 years. Those costs would presumably be offset by a series of assumptions, among them the accrued savings from lower prescription costs and a reduced administrative burden on hospitals. But most of the savings comes from the assumption that doctors and hospitals would make do with a radical reduction in payments—up to of 40 percent less than what they get from private insurers—without negatively affecting the quality or availability of care.

Environmental and economic policy aren’t the only public affairs in which the Democratic Party has allowed their youngish left flank to lead them into uncharted territory. The party is also staking out new ground when it comes to law enforcement.

Amid congressional negotiations aimed at avoiding another government shutdown, Democrats came up with a new demand: They wanted to decrease the number of beds in Immigration and Customs Enforcement (ICE) detention centers. Democrats proposed and Republicans eventually agreed to a 17 percent reduction in the carrying capacity of ICE facilities, ostensibly with the goal of forcing the Trump administration to prioritize the arrest and deportation of violent illegal aliens. But the artificial cap on immigration officials’ ability to detain and remove any illegal immigrant from the country—not just at the border—marked a dramatic departure for Democrats.

It was only a decade ago that Democrats as prominent as now–Senate Minority Leader Chuck Schumer made a conspicuous point of using the phrase “illegal immigrants,” an expression that has fallen out of favor on the left, to communicate their commitment to enforcing immigration law and to protect low-skilled American laborers from unfair competition. Democrats at the time often voted in favor of provisions that strengthened border security. Today, not only do Democrats oppose Trump’s border wall, they’re talking themselves out of support for any physical partitions along the border with Mexico. “I’d take the wall down,” said former Texas Congressman and potential 2020 presidential aspirant Beto O’Rourke when asked if he would order the removal of existing border barriers. Senator Gillibrand seemed to agree. “I could support it,” she said, presuming that tearing down the partitions that currently separate the United States and Mexico made sense. Of course, it most certainly does not.

When on rare occasion these Democratic utopians deign to consider how the country will pay for their multitrillion-dollar schemes, the stop-gap measures they support are laughable. Representative Ocasio-Cortez suggested higher marginal “tax rates as high as 60 or 70 percent” on your “10 millionth dollar.” But only about 16,000 Americans showed that much taxable income in 2016, the last year in which relevant government data are available. Her tax hike would raise only about $720 billion over a decade, a little more than what the United States spends on discretionary non-defense items in a single year.

Anyone who took a passing glance at Ocasio-Cortez’s proposal knew that Democrats would soon be looking for a bigger pool of Americans to squeeze. That’s why Senator Elizabeth Warren proposed a “wealth tax.” As with so many progressive proposals, the value of this plan rests entirely on the notion that this idea is common to Europe, so why shouldn’t it be adopted here? But this, too, doesn’t get the job done. Two University of California, Berkeley, economists estimated that Warren’s plan for a 2 percent tax on the assets of households worth over $50 million and a 3 percent tax on those worth over $1 billion would raise about $2.7 trillion over a decade. That would just about match what America shells out for its entitlement programs in one year. Or, it would, if Warren’s proposal was consistent with the Constitution, which it almost certainly is not.

The 16th Amendment, which gave birth to the federal income tax, permits the government to “levy tax on incomes,” not to expropriate private property when the government wants it. The courts have upheld this amendment’s original parameters by finding that inheritance taxes are constitutional only if they target the transfer of wealth, not the wealth itself. Moreover, Warren proposes a 40 percent one-time “exit tax” on Americans who try to evade her tax by renouncing their citizenship. This over-broad and discriminatory provision infringes on basic rights. Even if it didn’t, it’s probably unenforceable.

If progressives are looking for a bigger pool of money to tax, they can find it most readily through economic growth. More jobs mean more people paying income and payroll taxes, to say nothing of consumption taxes they pay when they patronize local businesses, which use that revenue in turn to hire more people, and so on. But for some on the left, this reliable cycle of growth isn’t just confusing, it’s unwelcome. Take, for example, the campaign waged by New York’s progressives against Amazon’s plan to provide New York City with 25,000 new jobs, each averaging an annual salary of $150,000.

The centerpiece of their grievance—one that eventually led Amazon to conclude that investing in New York City simply wasn’t worth the aggravation—was $2.8 billion in tax incentives available not just to Amazon but any company that qualified. These activists insisted that this money would be better spent at home on much-needed infrastructure projects. “If we were willing to give away $3 billion for this deal, we could invest those $3 billion in our district ourselves if we wanted to,” a triumphant Ocasio-Cortez insisted. This exposes a fundamental misconception about what tax abatements are. That money can’t be invested in other programs because it hasn’t been earned yet. Earnings have not yet been generated from which the money would come. And now they never will. Only if one sees all income and revenue as public property to be doled out as a product of governmental beneficence could one adopt such a deluded view of tax incentives.

These progressives do not advocate a flatter and fairer tax code. They don’t resent tax incentives per se. They only resent this one firm, in part because it is so successful. Ocasio-Cortez was celebrating the preservation of the status quo at the expense of economic development and individual prosperity. This is what it means today to be a “progressive.”

The policies Democrats warmed to in their wilderness years are unlikely to be realized if one of them wins the White House in 2020, but that is cold comfort. An influential mass of Democratic voters support these radical ideas, and the party’s presidential candidates are campaigning on them. Democrats may be convincing themselves that the popularity of some of these proposals in polls insulates them from criticism, but that popularity has already proven illusory. If even gentlest incredulity can bring the whole progressive edifice crashing down, Democrats may want to consider going back to the drawing board while they still can.