Is it "moral" to plot against people?

Is it ethical to plot against people, and thus engineer their downfall?

Consequences have to be weighed you might say …. But by what criteria is the weighing? What entity is great enough to dictate terms?

Would you be willing to fight for what you have come to live by as what is right for you? How does one come to know what is right?

Why not? Does the fight against evil not sometimes require some planning?

Maybe it’s more correct to have a defensive posture and defend yourself against assailing pressures. Is that a suggestion of the OP?