Democratic Party presidential candidate Hillary Clinton.

In one of her speeches revealed by Wikileaks, Hillary Clinton admitted that she sometimes takes “public” positions that are at odds with her “private” position. In other words, she sometimes lies to the public about her true views. Only the most naive observers find it surprising that politicians try to deceive people in this way, or believe that Hillary Clinton is an unusual exception.

I. Lying to Facilitate Deals.

In an insightful recent article, Brookings Institution fellow Jonathan Rauch describes why such deceptions are common, and may even be beneficial in many cases:

In politics, hypocrisy and doublespeak are tools. They can be used nefariously, illegally or for personal gain, as when President Richard M. Nixon denied Watergate complicity, but they can also be used for legitimate public purposes, such as trying to prevent a civil war, as in Lincoln’s case, or trying to protect American prestige and security, as when President Dwight D. Eisenhower denied that the Soviet Union had shot down a United States spy plane….

Is it hypocritical to take one line in private, then adjust or deny it in public? Of course. But maintaining separate public and private faces is something we all do every day. We tell annoying relatives we enjoyed their visits, thank inept waiters for rotten service, and agree with bosses who we know are wrong….

Often, the only way to get something done is to have separate private and public truths. Behind closed doors, nothing is settled until everything is settled. Until the deal is done, everyone can pretend not to have decided anything. But the moment the conversation becomes public, plausible deniability ceases. Everyone knows I’ve made an offer. Angry interest groups, adversaries in the other party, and even purists in my own party start cutting attack ads and lining up challengers to prevent a deal and defeat me.

Rauch is absolutely right to point out that political duplicity is sometimes a necessary tool for facilitating deals, negotiations, and diplomatic maneuvering. But he does not consider two other major reasons why politicians lie, both of which often involve the manipulation of public ignorance.

II. Lying to Exploit Public Ignorance.

Political leaders often conceal their true views when the latter diverge from majority public opinion, or from the beliefs of a key part of their base. Both Barack Obama and Dick Cheney spent years concealing their then-unpopular support for same-sex marriage – only coming out of the closet when the political winds changed. Well-informed observers knew that their true views differed from their public positions long before Obama and Cheney openly admitted it. But they nonetheless kept up the pretense because it did effectively fool some substantial number of less knowledgeable voters.

Some of Hillary Clinton’s deceptions probably fit this pattern, as well. For example, she and her advisers likely know that a $15 dollar minimum wage is a dangerous idea that will cost jobs, but pretend otherwise in order to please the Democratic Party’s base. During the Republican primaries, Ted Cruz demonstrated another variant on this type of political lying by trying to deceive voters about his record on immigration policy. Cruz likely knew that many voters did not know about the details of his record, and would no take the time to check it carefully.

Widespread voter ignorance also incentivizes another common type of political deception: lying about the nature of your policies in order to overstate benefits and conceal possible downsides. The most impressively successful recent deception of this type was Barack Obama’s promise that, under the Affordable Care Act, “if you like your health care plan, you can keep it.”

As MIT economist Jonathan Gruber, a key architect of ACA, put it, this deception was one of several ways in which the act was passed by exploiting the “stupidity of the American voter.” Gruber was wrong to conflate ignorance and stupidity, but right to recognize that the Act would probably not have passed in its current form had Obama admitted the truth back in 2010, and that he succeeded the by exploiting public ignorance. Well-informed observers knew from the beginning that the Obamacare individual mandate would force many millions of people to give up plans that they liked. But less knowledgeable voters were more easily fooled.

Obama’s deception was extraordinarily successful, and a deserving winner of the Politifact Lie of the Year award. But such tactics are not unique to Obama, or to liberal Democrats. Their Republican adversaries are no slouches in this department themselves. Those Republicans who think that Donald Trump is somehow an alternative to the culture of lying created by “establishment” politicians should remember that he himself lies and exploits public ignorance on a truly massive scale, even joining Obama as a winner of the Political Lie of the Year Award.

III. Is Political Lying Always Wrong?

Voters hate dishonest politicians, often for good reason. It is easy to see how political lying might cause harm. But sometimes politicians might actually be justified in lying to the public. Georgetown political philosopher Jason Brennan argues that such deception is defensible if it prevents an ignorant or malevolent electorate from pushing through harmful and oppressive policies.

For example, if a bigoted electorate favors slavery or racial segregation, a candidate might be justified in pretending to support these positions himself, and then reneging on his campaign promises when he takes office. Similarly, if you believe that passing the Affordable Care Act was the only feasible way to improve the badly flawed health care system, you might agree with Jonathan Gruber’s view that Obama’s lies about it were justified. Telling a few whoppers might be a small price to pay for saving the lives and health of millions. Political lying is generally wrong, as is the exploitation of ignorance generally. But sometimes, committing these sins might be the only way to avoid much greater evils.

That said, the routine use of lying and exploitation of public ignorance probably causes more harm than good. It also likely contributes to the atmosphere of suspicion and partisan hatred that helps make public opinion even more ignorant and illogical than it otherwise would be.

Given the structure of the political system, widespread deception may be unavoidable. Politicians who refuse to lie and exploit public ignorance are systematically disadvantaged relative to those with fewer scruples, and win fewer elections because of it. Ironically, the very same voters who hate dishonest politicians regularly reward deception by doing a terrible job of sifting lies from truth – especially when the lies reinforce their preconceptions.

The public ignorance that makes lying an effective political strategy is extremely difficult to overcome. Some of the resulting lying may even be justified. Still, we might wonder whether so many of our important decisions should be made by a system where lying is just politics as usual. Perhaps we should consider alternatives that do might curb the influence of ignorance and lies..