That was the reasoning used by America when they funded the Taliban to fight the Russians...
... And when they funded Saddam to fight Iraq.
Please note that any abuse in this post is both intentional and deserved.
Anyone that feels the need to further point out that it contains abuse is clearly a total fucking moron who's also insulting YOUR intelligence by pointing out the bleeding obvious as if you were too fucking dumb to notice it.
This has been a public service annoncement by Fork Me. Have a nice fucking day.