Is 20% ethanol in gas a good idea?

Some officials in Minnesota are proposing that all gasoline be mandated
to contain 20% ethanol. Can all engines safely run on a 20% ethanol
blend ... or might this be hard on the engine or fuel system? Ethanol
burns cleaner, but has less energy than gasoline. Critics say ethanol
requires subsidies, and a high amount of energy to produce. I remember
one critic claim that it takes more energy to produce ethanol than can
be derived from it in an auto engine: energy (gas, electric, etc.) to
plant, fertilize & harvest the corn, process it into alcohol, and
transport it. There's enough politics in this ethanol push to make me
seriously question it. Does anybody have any data or technical info on
inceasing ethanol in gas? Does any other state have ethanol blends
higher than 10%? And, what luck has there been with the E-85 (85%
ethanol) blend that some vehicles can use? JM