Iowa, Indiana, Kansas, and several other farm states grow a lot of corn. More than America can eat or export (even after we stuff our faces with corn-fed hamburger meat, corn chips and high-fructose corn syrup.)
Hey, wait: you can make ethanol out of corn. And everyone is worried about Peak Oil. If the government mandates "renewable" ethanol be added to gasoline, farmers in those states (and megacorps like Archer Daniels Midland) will make more money.
Iowa and those other farm states have a disproprtionate influence on Presidential elections, thanks to the Electoral College and the way we do primary elections.
Having mentioned the political lobby aspect of American practice of blending in alcohol myself, I think you can see you miss the point of what I said--which is that low percentages of alcohol mixed into gasoline is quite normal and widespread today. If it were so direly harmful as
@marathag implied, people would either be forced to recognize the sacrifice and only agree to purchase mixed fuel like that because it was much cheaper, or out of patriotism, or some other extraneous motivation, and be aware of a major price they are paying for the tradeoff. And others would simply flatly refuse to buy the inferior and allegedly damaging fuel mix, at any price, and make a big legal and political stink about it if lack of availability of alcohol-free gasoline due to market conditions leaving them none or still more due to legal banning of the pure stuff deprived them of their preference. They might lose, and protest the tyranny of the ethanol lobby.
What would not happen is that we all just quietly accept it, as perfectly equivalent to other gasoline options, and drive on for the lifetime of a car, decades or more, without running into any extraordinary mechanical issues involving the engine or fuel system that our ignorance failed to warn us of.
I am not a particularly technically savvy motorist, and could have been abusing my cars with a bad fuel mix in dumb ignorance, but in my experience, none of many issues various cars have presented me with ever seem to have emerged from using the wrong fuels. I've had loads of other issues, but never that.
Or let me backtrack a bit--I can think of two serious and costly issues that might conceivably have some bearing on the fact that I will indifferently put fuel with ethanol in it. But first of all, I suspect all my current car's problems relate to being a terrible design by a terrible company that did lots of stupid and bad things in making it; I suppose this might involve failing to alcohol-proof it as well as other designs typically are. But secondly, I am not such a dummy as to not ask my mechanics whether I did something wrong and what they recommend to avoid the same problem in the future, and none of them ever say "don't buy gas with alcohol in it." I'd pay attention if they did.
The sorts of problems that could conceivably relate to using alcohol in the fuel never bothered me in a few decades of motoring with four other cars by different makers, one of them a 1975 Chevette.
And meanwhile, if I am a fool about proper care and maintenance, others would not be. And I just don't hear any general chorus of complaint about the evils of alcohol in gasoline, in modest amounts. I've certainly heard a little bit of naysaying, but from sources I don't consider particularly savvy.
In the presence of the ongoing prevalence of gas being sold with ethanol additives, and the near total absence of any clamor against it, it is hard to think marathag is not exaggerating the problematic aspects of ethanol with his sweeping, absolutist denunciation. Or rather, since I myself did suggest that alcohol might indeed have been seriously problematic in the 1920s and its ubiquity today is due to having made some effort to solve the problems as
@Workable Goblin said has been done, it is the universality and totality of marathag's condemnation I question. He's saying it a bad solution in every context, and that seems not to be the case given the acceptance of it by a huge percentage of American drivers--I am tempted to say "all of them" but I have hardly surveyed the landscape. All I know is that if I pop into a random gas station for a fill up, I am quite likely to find a notice saying I am putting some alcohol in, and this never seems to be a problem. Since I am not seeking out a particular brand nor always striving for the absolute lowest price, just pulling in at the next station unless something seems egregiously wrong with it, I suppose most everyone does pump in some ethanol in the mix sometimes unless they have a bee in their bonnet about it or live in a region where this practice is less common.
But I don't live in the tall corn country either; my experience is with the markets of California and Nevada, and I think the ethanol is in there not because of some almighty corn lobby being strong in my region but because it is a cost/effective solution that does not cause harm...today. God knows how bad it might have been in the 1920s, or maybe you, marathag and Workable Goblin all do know exactly how dumb it would have been back then.
The question on the site is, what could have been done in the 1920s and '30s or anyway long before the 1970s to get the lead out. If alcohol is no good as an answer to that question, it was not my only or first suggestion.
Which was to use diesel instead of Otto cycle engines.