Why doesn't Superman just kill Lex Luthor

Why does Lex Luthor want Batman dead?

Lex doesn't actually want to kill Batman - he wants to kill Superman.

Everything Lex Luthor in Batman V Superman want to do : Dawn of Justice is to kill Superman fearing that a man as powerful as Superman will one day become some kind of dictator and use his god-like powers to take over the world.

Lex forces Superman to fight Batman by taking Martha Kent hostage, hoping that Batman will use the Kryptonite he stole from Lex to kill Superman - which almost happens.

It's worth noting that Lex has been luring the two into battle for a while now and has launched a series of events that lead Bruce Wayne / Batman to the same conclusion as Lex - that Superman is too dangerous to live.

As such, Batman is nothing more than a pawn in the game Lex Luthor plays.

Mishra Shreyanshu

Did Lex expect Bruce to enter his facility and steal this Kryptonite? Coz, it was clear that Lex had intercepted the checks on Keefe and mailed them back to Bruce so that one day Bruce would take steps to kill the Superman. If Lex has planned a fight between Bruce and Kent well, then Bruce himself needs Kryptonite to get stronger.

Dr. R Dizzle

@MishraShreyanshu I'm not 100% sure about that as I haven't seen the movie since it was released about 6 months ago, but I think so. You must also remember that Lex had Doomsday as a backup plan in case Batman failed to kill Superman.

Dave

I would add that if Batman fights Superman (assuming one of them kills the other), Lex wins no matter who comes out victorious. Either Superman is dead or Lex has clear evidence that the alien is as dangerous as he said, which will turn public opinion against Superman. Either way, he wins. As long as one kills the other. Of course, if that doesn't happen (as it didn't) then he has his backup plan to unleash Doomsday, a monster he believed he could control.