Militate vs Mitigate
Militateverb
have force or influence; bring about an effect or change
The difference
To militate is to weigh heavily as a factor, usually against something. To mitigate is to make less severe. The evidence militates against his account; the apology mitigated the offence.
How to keep them apart
You militate against; you mitigate something. "Mitigate against" is the common error.