Paul Sancya / AP

Last week, watching the 2020 Democrats spar over climate change, I thought of 2008, and the early fight over health-care reform. Eleven years ago, the high-stakes Democratic primary was descending into acrimony, and one of America’s most prominent left-wing pundits took a side.

Citing a new study by “one of America’s leading health care economists,” the pundit wrote: “If Ms. Clinton gets the Democratic nomination, there is some chance—nobody knows how big—that we’ll get universal health care in the next administration. If Mr. Obama gets the nomination, it just won’t happen.”

Clinton, the dreamy radical; Obama, the realist reformer? That quote appeared in a New York Times column by Paul Krugman, the Nobel Prize–winning economist. Though his analysis might seem backwards now, he believed it was Senator Hillary Clinton’s plan that could make universal health care possible. Senator Barack Obama’s proposal, meanwhile, seemed to dash progressive hopes.

This is not exactly how most Americans remember the 2008 election—and this is not necessarily how the election was seen at the time. But it reveals how preliminary our national understanding of health-care reform was in 2008, and how little the chattering class understood the challenge of changing the system.

The only question is whether this year’s debates will one day feel as outdated as 2008’s battles do now.

The best, most substantive discussion of how to address climate change that I’ve ever seen in high-level American politics happened last week. From 5 p.m. to midnight on Wednesday, 10 Democratic candidates took to CNN’s stage and explained how they would address “the climate crisis.” They bragged about their records, explained the nuances of policy, and answered detailed questions from the audience. For a seven-hour-long broadcast about the end of the world, it was strangely refreshing: For one evening, climate change got serious, sustained attention on national television.

And all that attention actually seemed to work. I’ve long felt that political journalists’ concern about climate change far exceeds their knowledge: Talking heads might know that climate change arises from every corner of the economy, but if given the chance, they ask candidates about whether they turn out the lights after leaving the room. Yet the CNN anchors—and the candidates themselves—discussed climate change as a challenge closer to what it really is: not an environmental problem, but an economic dysfunction with dire consequences for common prosperity, public health, and global order. “Climate is not a separate issue,” said Senator Cory Booker. “It is the issue, the lens, through we must see everything that we do.”

For this line, Booker should thank Governor Jay Inslee of Washington State, who campaigned on the line that climate change “isn’t a single issue” but one that touched “every issue.” Inslee dropped out of the 2020 race last month, but his departure has bestowed him with new influence. Journalists and other candidates can now openly praise his more than 200 pages of climate plans, and he alone can now credibly criticize or compliment other candidates’ plans. His rhetorical fingerprints were all over Wednesday’s town hall. Senator Elizabeth Warren has already adopted some of his plans verbatim.

But it’s not just Inslee who has reshaped the national climate conversation. As much credit, if not more, resides with the Democratic Party’s resurgent left. Democrats now regularly make two arguments that I first saw from the party’s progressive flank: that the fossil-fuel industry poses a special obstacle to climate action, and that the structure of American governance makes climate action hard.  

Senator Kamala Harris combined these critiques. “It’s not a question of debating the science,” she said. “It’s a question of taking on powerful interests, taking on the polluters, understanding that they have a profit motive to pollute.” If the Senate failed to pass a Green New Deal, she would press to end the filibuster.

In a literal sense, too, the left created the conversation that took place Wednesday. The town hall happened only because activists spent months pressuring the Democratic National Committee to hold a climate-focused debate. The party rebuffed their efforts, but they have already succeeded, somewhat: During the 2016 debates, climate change got five minutes and 27 seconds of airtime. During this primary it received, in this town hall alone, seven hours.

Former Vice President Joe Biden, the major candidate who has struggled the most with the new, more left-wing climate conversation, has officially adopted some of the tenets of activist ideas—early in his candidacy, Biden released a fairly aggressive climate plan that praised the Green New Deal and called for $1.7 trillion of federal spending on clean-energy R&D. (For reference, that is more than 600 times what the government spends on energy R&D today.) Yet at the town hall he flailed while trying to explain these policies, and many of his sentences seemed to end mid-thought. And when he faced questions from young activists to his left, he adopted a muddled, pleading tone.

“Look, I just—just look at all the organizations that many of you belong to, how they’ve rated my plan,” he said. “On balance, it’s been B-plus, or beyond that, by every one of these organizations.” Make me president—I’m B-plus! does not seem likely to enter the annals of great campaign slogans.

Beyond any one candidate’s performance, the town hall was, on the whole, remarkably useful. Both the anchors and the audience asked good questions. The country’s ability to fight climate change will require rank-and-file political journalists to understand the nuances of climate policy, and to ask intelligent questions about it. CNN’s town hall showed that they can—and, more important, it showed that climate policy is likely to benefit from more public attention, not less of it.

Even with all this momentum, history tells us that some lessons can only be learned from experience. Despite Krugman’s advocacy, Obama, of course, won the 2008 primary. Many ideas that both he and Clinton endorsed during the primary—such as a Medicare-inspired public option—did not find enough support in the Senate, and they remain goals of health-care reform today. Yet the policy that Krugman admired so much in Clinton’s plan, the idea that he thought would ensure universal health care, actually did pass.

That idea? A legal requirement that every American had to buy health insurance. This “individual mandate” became the core of the Affordable Care Act, but it was also immediately very unpopular. In 2012, the Supreme Court’s liberal justices bargained with Chief Justice John Roberts to save it. Their efforts were only half-successful. Before Krugman’s column turned 10, President Donald Trump and a GOP Congress had repealed the mandate entirely.

The policy that was once prophesied to bring about universal health care ultimately almost doomed the effort. If climate advocates are very lucky, then some of their most cherished proposals now will seem just as foolhardy in 2029.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.