The first line of Cass Sunstein’s latest book, The Ethics of Influence, announces: “We live in an age of psychology and behavioral economics—the behavioral sciences.” For Sunstein, a Harvard law professor and former Obama administration official, this is as momentous a statement as saying we live in an age of antibiotics, steam engines, or the Internet. But just saying that nudges are here to stay does not make it so. In fact, if their future were not in doubt, why the need for yet another book on the topic—and so soon after his Father’s Day-gift-ready book on Star Wars—arguing that they should be here to stay? Like the president he served, Sunstein is now focused on cementing his legacy.

THE ETHICS OF INFLUENCE: GOVERNMENT IN THE AGE OF BEHAVIORAL SCIENCE by Cass R. Sunstein Cambridge University Press , 234 pp., $29.99

Sunstein’s work on behavioral economics found its ideal patron in President Obama, and not simply because the two men knew each other from their days teaching at the University of Chicago. For a presidency born in economic catastrophe and plagued by an anemic recovery, gross inequality, and a hostile Congress, there was always the question of how to use executive action to salvage something positive in the face of a hopeless political situation. Enter nudges, a means of influencing people’s decisions without the need for coercion or mandates; crucially, a nudge can secure policy success without requiring Congressional approval. This is not exactly what the candidate of hope and change had in mind by “hope and change,” but it would have to do.

In 2015, President Obama issued an executive order committing the U.S. to “using behavioral science insights to better serve the American People”— a directive that Sunstein proudly republishes as Appendix C of his latest book. “The importance of this executive order cannot be overstated in view of its likely role in making behavioral science a permanent part of American government,” he writes. The White House’s new Social and Behavioral Sciences Team just issued their second annual report on the many ways they’ve used behavioral insights to improve government. Sunstein is now pushing for the creation of a Council of Psychological Advisers, on a par with the Council of Economic Advisers, to explore “when people could benefit from a nudge.”

But before America sees a Secretary of Nudges added to the Cabinet, there are two hurdles to clear. First, there’s the next president, who can let these efforts whither on the vine, if he or she doesn’t rescind them with a stroke of a pen. The only mention Hillary Clinton’s campaign website makes of “behavioral science” regards mental health, and as for Donald Trump, let’s just say he’s more of a coercer than a nudger.

Second, plenty of critics question the propriety of nudges. The idea of technocratic nannies shaping our choices and behavior behind the scenes smacks of gross manipulation. And even if we don’t always make the best decisions, and even if our welfare would be vastly improved by such maneuvering, what about our autonomy? Yes, modern life is complex and we need help to navigate it, but surely philosopher Jeremy Waldron was onto something when he concluded his New York Review of Books critique of Sunstein’s work, “I wish, though, that I could be made a better chooser rather than having someone on high take advantage (even for my own benefit) of my current thoughtlessness and my shabby intuitions.”

Thus the need for Sunstein’s defense of nudges in The Ethics of Influence. And a defense is exactly what we get in this tightly argued and admirably clear book. He frequently compares nudges to a GPS system that—uncontroversially, of course—helps direct us to where we want to go. Repeatedly when he raises an ethical quandary for discussion, he quickly turns to the least controversial use of nudges, such as anti-smoking initiatives or nutritional labels, to argue that nudges (largely) defuse it. Within the space of two chapters, Sunstein twice repeats the previous quote and another from Waldron’s review verbatim to tee up a response. These passages have clearly stuck in Sunstein’s craw, and he mounts a vigorous answer.

The result is an excellent primer of the relevant debates on nudges, and a sharp rejoinder to the more superficial objections. But we do not get a bona fide philosophical inquiry into the underlying ethical issues—one that would plow headlong into the most difficult dilemmas, rather than immediately veering onto safe ground. And this is the sort of investigation that is sorely needed.

Sunstein and his then-colleague, University of Chicago economist Richard Thaler, introduced the behavioral economics term “nudge” to our lexicon with their 2008 bestseller Nudge: Improving Decisions About Health, Wealth, and Happiness. They promoted nudges as forwarding neoliberal economist (and University of Chicago giant) Milton Friedman’s ideal that people should always be “free to choose.” “Libertarian paternalism” became the political slogan for their incipient policy revolution. Nudges could paradoxically enable the state to shape the public’s choices for the better (paternalism) while maintaining their freedom (libertarian). Sunstein and Thaler had found the Golden Mean between Reagan free-market conservatism and FDR state-guided liberalism.

Nudges work by exploiting various cognitive biases that empirical research has demonstrated in human behavior. For example, we are less enticed by the less nutritious food if we’re confronted by the calorie total at the moment of purchase or we have to hunt for it because it’s been placed in an inconvenient spot in the cafeteria line. We tend to follow what other people do or what we perceive as popular, and we tend to put off decisions if we can get away with it, because of the cognitive cost incurred when we have to stop and think about our next move.

Defaults—the pre-selected choice you end up with if you do nothing—are an especially effective way to exploit such procrastination. Defaults signal to people what they should do and since most people, due to the inertia of life and the burden of decision-making, will do nothing, most people will go along with the default. But since defaults leave options open, no one can complain that they didn’t have the chance to act otherwise. For important decisions that require careful deliberation and should not exploit such human frailty, such as whether to become an organ donor or to be resuscitated by medical personnel, we can reject defaults and require that people make a decision (“forced choice”) and even give them a brief explainer on the options.

Sunstein cogently argues that nudges add a valuable tool to the government’s toolbox alongside its other, blunter instruments, such as prohibitions, taxes, and subsidies:

If freedom and welfare matter, coercion is often best avoided, and so the last decade has seen a remarkable rapid growth of interest in choice-preserving, low-cost tools, sometimes called nudges. For example, many governments are keenly interested in disclosing information; in providing reminders and warnings; and in using default rules, which establish what happens if people do nothing. Some of those approaches save a lot of lives.

“Choice-preserving” and “low cost” are the key traits of the nudge’s appeal. Unlike government mandates, nudges always preserve people’s freedom of choice. Various behavioral biases mean that many of us will act in predictable ways that—if government “choice architects” are doing their job—will benefit us and society at large, but our freedom to act otherwise is preserved.

Take, for example, enrollment in retirement plans, which is typically a complex and painful process. Since people are busy, don’t like to incur cognitive costs, and often go along with the flow of life, many are liable not to bother to enroll at all, to their own detriment. But if companies are required to enroll all employees in a basic plan, unless the employee chooses to opt out, more people will be enrolled in retirement plans by default (win) while those who don’t want to will be allowed to opt out (win). And nudges are “low cost” in the sense that they do not incur significant material costs on individuals (If they did, such as penalties or fees, they wouldn’t be nudges) and they are comparably cheap for government to implement.

The core of Sunstein’s ethical defense of nudges is persuasive. Choice architecture is inevitable: Circumstances always influence our decisions, whether the government deliberately shapes those circumstances or not. As long as the government is transparent about what it’s doing, why not try to help shape those circumstances so that we make better decisions? I don’t know about you, but I for one appreciate help with tasks fraught with anxiety such as avoiding trans fat or opening a line of credit. When I get the help—and we do often get help through government intervention, though we don’t notice—I typically feel more relieved than infantilized.

And yet this whole argument rests on assumptions about which Sunstein is rather rosy. It assumes a well-functioning government that is transparent and responsive to us. “Certainly choice architects should be focused on the welfare of choosers, rather than their own,” Sunstein intones, adding parenthetically, “In a well-functioning market system, that focus is promoted by competitive forces, at least under optimistic assumptions.” How optimistic is it to assume a well-functioning government after Citizens United?

Sunstein also assumes a level of trust in the good intentions of public officials that is simply not shared by the public. One may feel—this reviewer, for one—that the reason for Sunstein’s enthusiasm, and for the Obama administration’s support, for nudges is that they can “attract support from people with diverse theoretical positions.” In other words, in an age of congressional gridlock and partisan bickering, it offers a glimmer of hope that government can do a little something that’s uncontroversial and positive. When aspirations for hope and change are disappointed, technocratic fixes will do.

Do people like nudges? Sunstein polled 563 Americans for the book, offering a range of survey questions across the gamut of possibilities, and in chapter six he reports those findings. The data show “widespread, cross-national support for nudges” of all the various sorts used in real life. Support tends to drop when the nudge seems manipulative, when people incur losses without their active consent (e.g. when one is defaulted into a higher cost option), or when they do not trust the motivations of the choice architect.

Yet there is a troubling empirical finding for someone investigating the ethics of influence: “If people are told that they are being nudged, they will react adversely and resist (and hence be nudged less or not at all).” Sunstein then raises an excellent question: “Do we have reason to question the kinds of influences for which transparency turns out to be self-defeating?” Indeed, does transparency require every nudge to have an informational pre-nudge about being about-to-be-nudged? This is a fascinating question that gets to the heart of an ethical dilemma, but does not exactly suit Sunstein’s apologetics. In a short, dissatisfactory discussion, he turns to his favorite crutch—informational disclosures are transparent!—and admits there is little evidence; he cites one study supportive of transparent defaults that depended on an online questionnaire with a low-participation rate. He determines that “There is a great deal to learn here, and it bears on the ethical questions.” Indeed, to the extent that ethical nudges require transparency and transparency negates their effectiveness, the viability of the whole project comes into doubt.

A similar eye-opener occurs in the next chapter, which also delves into the concrete, namely the use of green energy defaults for consumers, which typically cost more but are better for the environment. On page 175 of a 212-page treatise touting the “choice-preserving” advantages of nudges, we read this:

Default rules may be more sticky for low-income workers than for their higher-earning counterparts. One reason may be that low-income workers have a great deal to worry about and so are less likely to take the trouble to think through and to alter the default rule.

He soon adds:

There is general evidence that when people are highly informed and experienced, and hence know what they want, they are far less likely to be affected by the default rule. One reason is that the effort tax is worth incurring. Another reason is that some people actually enjoy searching extensively and making their choice independently of defaults.

And let me offer another reason: Because their class enables them to make a choice. Those who are economically secure have the mental space and leisure to devote themselves to complex choices; for some it presents a sort of pleasant hobby. The poor, by contrast, have too many other things to worry about to deliberate about niceties such as energy plans. Recent research even suggests that economic distress can lower IQ by an average of 13 points.

This is a crucial problem about the ethics of nudges that cannot be stressed enough: Do nudges preserve freedom of choice for everyone, or only for those people who are resourced to exercise that freedom? It is also another fascinating question worth deep exploration. Why didn’t this come up earlier in a book dedicated to the subject and demand more in-depth treatment? But then again, if you’re offering a legal defense or trying to cement your legacy, you do not dwell on the problematic.

In the book’s penultimate chapter, Sunstein compares nudges with mandates and argues how the freedom-preserving nature of the former helps resolve problems with the latter. But there’s one positive about mandates Sunstein fails to mention: They affect everyone equally, regardless of their choices or abilities to choose. For a book nominally dedicated to the morality of nudges, it’s surprising that one core value fails to gain a mention, namely justice.

Obama’s embrace of Sunstein’s ideas is on a par with his enthusiastic adoption of tech fixes, highlighted by his founding White House start-ups for upgrading government technology, his talk of a post-presidential career in venture capitalism, and his recent guest-editing gig for Wired magazine’s November issue. Obama has seized the low-hanging fruit, the uncontroversial improvements he can secure by his own efforts, because his higher goals were unreachable. If Clinton becomes our next president and has a genuine opportunity to make America a more just and fair nation—say, if the Democrats retake control of Congress—why use nudges? Sunstein has offered his nudge with The Ethics of Influence. But Clinton is free to make a different choice.