Historians Against Trump, a group of over 600 academic historians, recently posted an open letter urging voters to oppose the GOP nominee. The letter relies in significant part on their professional expertise and “the lessons of history,” as understood by “[h]istorians of different specialties” who have expert insight into “the ominous precedents for Donald J. Trump’s candidacy and the exceptional challenge it poses to civil society.” The group’s appeal to their disciplinary expertise has attracted the ire of critics such as postmodernist law and literature scholar Stanley Fish, who wrote a New York Times column attacking HAT:

By dressing up their obviously partisan views as “the lessons of history,” the signatories to the letter present themselves as the impersonal transmitters of a truth that just happens to flow through them. In fact they are merely people with history degrees, which means that they have read certain books, taken and taught certain courses and written scholarly essays, often on topics of interest only to other practitioners in the field.
While this disciplinary experience qualifies them to ask and answer discipline-specific questions, it does not qualify them to be our leaders and guides as we prepare to exercise our franchise in a general election. Academic expertise is not a qualification for delivering political wisdom.

I. Why Expertise Matters.

Contra Fish, experts often have good reason to suppose that they have greater insight into political issues than ordinary voters do. And, at least in many cases, the latter would do well to pay more heed to expert opinion, not less.

The idea that expertise is not a qualification for delivering wisdom would be immediately dismissed as laughable in almost any context other than politics. If you need to address a medical problem, a doctor’s opinion should count for more than that of a random sample of the general public. If your faucet is leaking, a plumber’s view on the subject is going to be a lot more valuable than mine.

Similarly, political controversies often involve complex policy issues on which experts on public policy have greater insight than laypeople. Not because they are generally smarter or more virtuous than the rest of us, but because that’s their field of expertise. This is especially likely to be a true in a world of widespread voter ignorance where most voters are “rationally ignorant” about policy issues, and often don’t even know very basic facts about government and public policy.

Historians are pretty obviously among the the experts who are likely to have useful insights on Trump’s candidacy. There are many historical precedents for Trump’s xenophobic program of massive restrictions on trade and immigration, targeting civilians, and weakening protections for freedom of speech.

Scholars who have studied that history will often have greater insight on Trump’s proposals than laypeople who have not. Not all the signers of the HAT letter have specialized expertise on historical issues relevant to assessing Trump’s campaign. But many do. Voters would do well to take advantage of that insight. Even the best experts aren’t always right. But, within their areas of expertise, they are more likely to be so than laypeople are.

II. What if the Experts are Biased?

That’s why some of the most useful evidence of expert opinion comes from studies that control for the ideology and partisanship of the experts consulted. For example, Bryan Caplan finds that, after controlling for these and other variables, economists are far more optimistic about the economic effects of free trade and immigration than laypeople are. That doesn’t definitively prove that the economists are right. But it does suggest that the divergence between them and ordinary voters really is the result of disciplinary expertise, as opposed to ideological bias.

Many of the historians who signed the HAT petition are probably ideological liberals who strongly oppose the GOP generally, not just Trump. But Trump’s candidacy is noteworthy for attracting strong opposition even among many policy experts who are not on the left, and usually support the GOP against the Democrats (myself included). Consider, for example, this statement signed by a wide range of Republican foreign policy experts. Not all policy experts are anti-Trump. But he has attracted a wider range of expert opposition than any other major-party nominee in my lifetime.

Widespread expert opposition to Trump doesn’t by itself prove that the electorate should reject him. Just as the dominant view among doctors is sometimes wrong about medical issues, so the dominant opinion among policy experts is sometimes wrong about political issues. Still, widely held expert opinion is at least worthy of serious consideration by laypeople, especially when it cuts across ideological and partisan lines.

At the very least, if voters had greater familiarity with experts’ critiques of Trump, it would be tougher for him to exploit public ignorance, which has been a major factor in his success thus far. Trump is far from the only politician to exploit public ignorance. But he has benefited from it more than most.

III. The Role of Values.

Some argue that expert opinion on political issues is of little relevance because political disputes are really about differences in values, not facts. Much of the time, however, that simply isn’t true. Survey data shows that most elections turn not on deeply divergent first principles, but on disagreements about how to achieve widely agreed upon goals, such as strengthening the economy and protecting national security. These are in fact the very objectives most often emphasized by Trump himself, embodied in his claim that he is going to “make American great again.” Expert insights are surely relevant to assessing whether his platform is actually likely to achieve the promised “greatness.”

Even when it comes to issues that do turn on differences in values, expertise is sometimes relevant. Not everyone is equally good at assessing the implications of the principles they adhere to, or at figuring out which values might be more important than others. For example, it may be the case that Trump’s positions on issues such as immigration actually contradict values that many of his conservative supporters hold dear, and do so in ways that may not be immediately obvious to people who have not studied the issues carefully. On values, as on facts, expert opinion has special value not because the experts are particularly smart or virtuous, but because they happen to know more about the relevant issues and have analyzed them more carefully.

Cynics might claim that I only advocate deference to expert opinion when it accords with my own predispositions, as is true in this case. Not so. For example, I give a lot of weight to the dominant view of climate scientists about global warming, even though it would be more ideologically convenient for me to conclude that warming is not a significant problem. When it comes to taking expertise seriously, I try to practice what I preach, even if it cuts in favor of positions I dislike.

We should not slavishly follow expert opinion. But we should also avoid the opposite, probably more common, mistake of thinking that experts have no greater insight on political issues than laypeople.

NOTE: For those interested, the History News Network has compiled a wide range of other commentary on the HAT letter. I particularly agree with many of the points made in this excellent post by Daniel Drezner.