So they have intercontinental ballistic missile and small nuclear warheads that now can hit deep into continetnal US. They have a mad, homicidal dictator who wishes to die.
He will not deescalate. He will launch against us sooner or later.
Either we attack and take them out before they launch, or we will retaliate after they launch against us, or we take out their launched missiles and silos if our missiles and lasers are good enough.