Thread:Collin the Guardian Spook/@comment-5266525-20140323232715

"mitigate - make (something bad) less severe, serious, or painful."

"negate - make ineffective; nullify."

If you negate something you are automatically mitigating it because you are reducing its effect to nothing, in a sense. Hence when dealing with (say) spellshields and Jax's Empower, there is no distinction between the two. 