Earlier this week, both Democratic and Republican members of Congress pilloried MIT economist Jonathan Gruber at a hearing before the House Oversight and Government Reform Committee. Gruber’s sin was a series of speeches in which the key architect of Obamacare pointed out that the law was passed by manipulating “the stupidity of the American voter.” Republicans understandably want to exploit Gruber’s comments for political advantage. Democrats, just as understandably, want to distance themselves from him.

Lost in the hysteria is the painful reality that Gruber’s statements were largely accurate. Exploitation of political ignorance did help get Obamacare passed, and the public really is ignorant about both Obamacare specifically and political issues generally. Political strategists in both parties are well aware of the realities of political ignorance, and act accordingly in planning their campaigns. Both Democrats and Republicans routinely praise the wisdom of the voters, even as they shamelessly exploit public ignorance. When grilled by the congressional panel, Gruber should have quoted Michael Corleone in “The Godfather, Part II”: “Senator [or, in this case, Congressman], we’re both part of the same hypocrisy.”

Obamacare only passed the House of Representatives by a narrow 219-212 margin. If instead of lying about how “if you like your health care plan, you can keep it,” the president had honestly admitted that his law would cause millions of people to lose their policies, the bill would likely have been defeated. The other deceptions emphasized in Gruber’s speeches may also have helped pass the law.

The deceptions probably would not have succeeded in the absence of widespread political ignorance. People who studied the plan carefully could readily tell that the administration’s statements were deceptive. Forcing millions of people to buy more comprehensive and more expensive health insurance plans than they had previously was an important element of the Affordable Care Act. As health care experts on both sides of the debate recognized at the time, it is a feature not a bug – an essential part of the plan. But most voters don’t pay close attention to the details of government policy, and therefore enough fell for the deceptions to enable the law to pass.

Gruber was also right to claim that voters are ignorant more generally, both about Obamacare and much else. Polls repeatedly show widespread public ignorance about many aspects of Obamacare, even after years of public controversy about the issue. A 2013 Gallup poll finds that those who are more familiar with the law are significantly more likely to oppose it than those who know less about it (though self-reported familiarity is not always a good proxy for actual knowledge).

Public ignorance about politics goes far beyond Obamacare. The members of Congress who denounced Gruber on Tuesday just went through an election campaign in which voters decided control of the House and Senate even as over 60% of Americans did not even know which party controlled which house before the election. Decades of survey data show that political ignorance is widespread, deeply rooted, and common among both Democratic and Republican voters.

The Republican politicians who have been attacking Gruber are not above exploiting ignorance themselves, when it is politically advantageous to do so, as they recently did in the case of the ebola virus. Before Gruber helped the Obama administration design and promote Obamacare, he helped Mitt Romney design and promote Romneycare, which served as a model for Obama’s law. In one of his videotaped speeches, Gruber recounted how Romney and Massachusetts Senator Ted Kennedy “ripped off” the federal government to fund Romneycare, a sleight of hand he called “Mitt Romney’s dirty little secret” about his health care law. Needless to say, this aspect of the law was not much mentioned by Romney in his efforts to promote his record during the 2008 and 2012 presidential elections. Ironically, the 2012 election pitted against each other two candidates both of whom had adopted health care laws in large part designed by Gruber, and sold to the public in part by exploiting political ignorance.

Gruber did err in making the common mistake of conflating political ignorance with “stupidity.” In reality, even smart people are often ignorant about politics, in large part because such ignorance is perfectly rational behavior, given the low probability that your vote will make a difference in an election. The problem of ignorance is also exacerbated by the enormous size, scope, and complexity of modern government, which makes it difficult even for more attentive voters to keep track of more than a small fraction of it. By making government even larger and more complicated than it already was, the enactment of the Affordable Care Act helped exacerbate the very ignorance that helped make its passage possible.

With some crucial caveats, Gruber’s statements about political ignorance were largely accurate. He should not have had to apologize for them. But while Gruber’s words were defensible, many of his actions were not. The real wrong he committed was not talking about political ignorance, but taking part in an effort to exploit it to pass a dubious law. The fact that he is far from the only politician or consultant to do so, does not excuse him. Gruber has also misled people about various conflicts of interest, such as posing as an objective, independent analyst about health care policies he was paid large amounts of money to help design. Recognizing the truth of Gruber’s statements does not mean we should excuse his misdeeds.

The issue of political ignorance and its exploitation is a major problem that goes far beyond Jonathan Gruber and Obamacare. Hopefully, the Gruber saga will lead more people to take the issue seriously.