Lauren WeinsteinOne of the reasons why Evil so often triumphs over Good, is that Good argues endlessly about whether or not its members are "sufficiently good", while Evil gleefully accepts all applicants.
Chuck@lauren As I recall, this observation was the impetus for the aphorism "The enemy of my enemy is my friend." It essentially cuts off debate on whether this ally is "sufficiently good" and replaces it with "is fighting the same enemy I am" which is a bar that is more easily met.
Rhinos Worry Me"Friend" feels a bit much.
I'd go with "The enemy of my enemy is potentially useful."