Can a person suing you for slander or defamation win a case if he then goes around slandering the person back?

[voliny13]

Yes, but the person could countersue and end up with an award of exactly the same size, in theory.

[kyledyr]

Can a person getting charged with murder or manslaughter and be thrown in jail if the prosecuting attorney killed someone else? Yes, but the prosecuting attorney would be charged with the same thing.

[freedom97]

Anyone trying to sue for slander or defamation has to prove very important and difficult things: that there was "actual malice" in the making of statements that the speaker KNEW was false and that those statements caused actual monetary damages. It's incredibly hard to prove all of those things. It's always better just to fight speech with more speech and let the truth win in the marketplace of ideas.