What does "third rail" mean? A reserve force that will never be used?

Third rail is a reference to electric trains where the electric runs on the third rail. Touching the third rail is dangerous and often deadly. In this context, third rail is an issue that should be avoided because it could cause damage to those that try to deal with it.

Most often either because the people have made up our minds and will destroy anyone in power who attempts to cross us or because the issue is so controversial that there is no hope of resolution and anyone who takes a position will get hammered by those who oppose that position. The main characteristic of a third rail is that it is known by all to be a place that no one can go without getting destroyed by the effort. An example of a third rail is the telling the American people that they must pay for all services that the government provides. The American people dont want to hear it, and will crucify anyone who insists upon saying such a thing.

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