Public support for big government — more regulation, higher taxes, and more social services — has reached the highest level on record in one of the most prominent aggregate surveys of American public opinion.

James Stimson, a political scientist at the University of North Carolina who’s one of the giants of American public opinion research, broke the news in a modest missive to a political science email listserv on June 6. He was sharing the news that the latest edition of Policy Mood, a composite look at American opinion across a range of polls on a range of issues, was available for public release.

“The annual estimate for 2018 is the most liberal ever recorded in the 68 year history of Mood,” he wrote. “Just slightly higher than the previous high point of 1961.”

This is a reaction to President Trump, but it isn’t narrowly about his most distinctive characteristics. Indeed, as you can see in the table, a leftward shift of views is a predictable response to a Republican president being in office.

But of course we’ve had plenty of Republican presidents since 1961, so the record-setting nature of the current index is a noteworthy development with potentially big implications for the future — if Democrats can surmount the challenges of political geography.

Policy Mood and the public opinion thermostat

Stimson’s Policy Mood is an effort to measure what the public thinks about not one particular policy question but the overall approach to policy that the government ought to take. It’s constructed by aggregating a bunch of answers to different questions from both big academic surveys, like the General Social Survey and the American National Election Survey, and polls done by commercial pollsters.

The idea, however, is to focus on the enduring sources of conflict in American politics — taxation, the government’s responsibility to spend more or less in different areas, and the merits of stricter regulation versus less red tape — rather than hot-button issues that come and go.

The Mood became very liberal in the early 1960s, and that set the stage for the Great Society, in which liberal ideas were enacted across a wide variety of topics — including Medicare and Medicaid, federal money for K-12 education, civil rights, voting rights, and the beginnings of environmental protection.

In the late 1970s, the Mood became very conservative, and set the stage for the Reagan Revolution, in which conservative ideas were enacted across a whole swath of policy areas — taxes went down, military spending went up, social assistance to the poor was pared back, and regulatory intensity diminished across the board.

One of Stimson’s big findings is that public opinion operates like a thermostat that acts to bring the political system into equilibrium, stopping it from moving too far to the left or the right. So while the sharply liberal Mood of the early 1960s set the stage for the Great Society, the actual enactment of the Great Society sent it in a rightward direction. The 12 years of Reagan-Bush governance later pushed the Mood steadily leftward.

One of the reasons Trump won in 2016 is that Mood drifted considerably to the right over the course of Obama’s eight years in office. Hillary Clinton won the Democratic Party nomination by promising to find ways to move the ball forward on progressive policy priorities, but the public mostly wanted a course correction in the conservative direction.

Trump, however, offered a lot more than the course correction, leading out of the gate with an unpopular health care bill that repudiated his campaign promises to “cover everyone” and then followed it up with an unpopular tax bill that repudiated his campaign promises to leave rich people alone and focus tax cuts on the middle class. Consequently, Trump is now personally unpopular and the thermostat is swinging significantly the other way — creating a big, but difficult-to-seize, opportunity.

It will be hard for progressives to seize this opportunity

One of the values of Policy Mood as a metric is that it has a clear relationship to the big macro-scale events in American politics. The Great Society is clearly visible, as is the collapse of the New Deal coalition under Jimmy Carter, the slow-but-steady erosion of public support for Reaganism, the sudden rightward shift of the 1994 midterms, and the general ebb and flow of thermostatic politics.

But the American political system does not perfectly translate public sentiment into policy outcomes. It is, instead, filtered through the mechanisms of party politics and the clunky machinery of congressional elections.

And here’s where Democrats have a problem.

One thing both parties have learned over the years is that the thermostat works predictably. If you lose an election, you can pretty much count on bouncing back. In 1981, Reagan was able to pass a lot of conservative policies even though Democrats actually had a majority in the House of Representatives. Some of that is because many of those Democrats (the so-called “Boll Weevils”) were themselves pretty conservative and ended up providing the votes that put the Reagan Revolution over the top. But that only worked because Democratic Party leaders let the bills come to the floor for a vote — something that modern party leaders wouldn’t do.

The perception at the time, however, was that Reagan had a “mandate” and it would be wrong or untenable to keep his priorities bottled up with procedural machinations.

In today’s politics, that won’t work. If Democrats want to take advance of the liberal turn of the Policy Mood by enacting progressive legislation, they’re going to need to concretely win elections and secure votes.

The 2020 Senate map is going to make it very difficult for Democrats to win a majority. But this isn’t a quirk of 2020. The 2018 map was also bad, and the 2022 map will be bad too. Indeed, if you aggregate votes across the 2014, 2016, and 2018 cycles, then Democratic candidates have won somewhere between 51 percent (if you assign the GOP all of the second-place candidate’s votes in California) and 55 percent (if you assign the second-place votes to the Democrat) of the popular vote. But Republicans have consistently held a Senate majority across this period. And even if Democrats did manage to eke out a narrow Senate victory, they’d still face the problem of the filibuster.

In other words, while the public is more open to a surge of activist government activity than at any time in the past six decades, the odds of actually getting such a surge remain relatively low.