An Emperor and Kings

Say a country has twenty leaders who want to rule the country.  Only one can rule at a time.  As the current leader, would it be best to...

Eliminate all who aspire to be rulers
Allow your rule to expire so others may rule
Deny further rule until you have a successor
Imprison/restrict others who want to rule or reduce them to poverty
Allow them to rule as governors or subordinate leadership positions

If you choose the last option, how do you prevent them from turning on you or revolting? 

read machiavelli. you'd learn a lot there...

simply instute governors below and if one of them fucks up, let him be executed as an example. the people will love you, because you saved them and the others will be too frightened to do something. why side with the people? because it is too hard to reign against them and every successor will have a hard time in reigning with terror. so if you'd survive a military coup, they'd want you back.

the problem of this is, that you'd need a strong army of your own (to prevent foreign nations from conquering you and securing yourself against other possible leaders) and you have to deny your governors to have their own forces