We make that decision all the time, and never learn that there are always more than two sides to any argument.
We are now pals with Pakistan, a military dictatorship and saber rattler.
We support shieks who are stealing their peoples futures and squandering it at Monte Carlo.
We prop up illegitimate governments in South America who are helping us in the drug war.
It can only been true in cases when one needs a friend where only an enemy stands. War on drugs helps us form alliances with these sorts of governments; had we no need to combat drugs, of course, then such an alliance is useless.
Being compelled to action will form all sorts of alliances. Ever play four player chess? 
It’s a stupid way of thinking, and I wish our leaders would stop using it as a mental crutch.
Gee, rjung, I take it you don’t play monopoly much. 
I believe that this mentality will form itself in situations where the opposing side is either reasonably equal to you, or quite a bit stronger. In such cases, any help, however tainted, looks good, and you are able to overlook anything else they might be doing in order to continue to maintain such help. If you are then able to finally make some headway, and no longer need their assistance, it tends to be harder to break contact, and start punishing them. It is my belief that this mentality should be only used very infrequently and when there is no other recourse. Also I believe that we should escape such alliances as soon as possible, and return to a position of condeming them for their abuses and problems.
Also keep in mind that in some of the examples present in the OP, taking action against the people would mean igniting the Middle East even further, something we are loathe to do for quite obvious reasons. In order to combat such things, we may light a greater fire, in a very sensitive time.
Have you ever heard of the concept of “the lesser of two evils”? In World War II our leaders aligned with Stalin against Adolph Hitler. One the threat of Nazi Germany was over, the alliance quickly disolved. Why did our leaders ally with a genocidal dictator? Because the Nazis were a more immediate danger than the Communists.
It is very easy to sit in moral judgement, in hindsight, with perfect information. It is very diferent when you are responsible for making decisions that affect the lives of 250 million people. de trop, you should take your own advice and understand that issues are generally more complicated than “Pakistan is a dictatorship”.
Monopoly is a board game with an artificial environment and artificial rules; using it as a guideline for real-world decisions is akin to using Carmageddon to practice for your driver’s exam.
And besides, it takes too long. 
Wouldn’t mind trying a few games of Illuminopoly, however.
I’m still trying to figure out the OP. de trop starts off by pleading for an understanding that the world’s politics exist in shades of grey (“We…never learn that there are always more than two sides to any argument.”) and then procedes to paint cetrtain governments in black or white (“Pakistan [is] a military dictatorship and saber rattler.”).
It seems to me that you answered your own question. The world is a very complicated place and sometimes you have to make decisions for which the correct path is very ill-defined and not much better than the wrong path. Sometimes you make the wrong choice and don’t realize it until you are hopelessly bogged down. The same thing happens in our own lives, also.
de trop, what do you suggest that our relationship with Pakistan should be at this point in history?
Well, rjung, it is a good thing I didn’t suggest we use Monopoly as a guideline for real-world decisions. I just wanted to note that the idea of “my enemy’s enemy” isn’t prima facie ludicrous, and is used more often than one thinks. (link doesn’t work, BTW)
Soon, you will explain why it is a stupid way of thinking. Won’t you?
Since you asked so nicely…
Generally speaking, “the enemy of my enemy is my friend” is too broad and too general for practical use, either in real-world situations or in artificial game environments. The context of the relationship must be studied; perhaps the EoME is an even bigger threat to us than the original enemy, or siding with either enemy would invite immediate retaliation from the other. Perhaps treating both enemies with equal distance would be the wiser move, allowing them to expend more energy fighting each other than fighting me. To use an automatic “the enemy of my enemy is my friend” rule ignores all of the possibilities and circumstances possible. If I’m hiking in the woods, get chased by a grizzly, and a cougar appears, embracing the cougar would not be the wise move to make (as opposed to, say, getting very far away from both of them).
And try this for the Illuminopoly link. It works fine for me…
When I first discovered the OP phrase many years ago, it was in a novel (I don’t remember which after all this time), but it was worded differently: “My enemy’s enemy is not my enemy.”
That wording has always made a lot more sense to me. It certainly doesn’t make party #2 a friend and doesn’t on its face require hideous entanglements.
Hmm, that’s wierd… the link worked for me at home but not at work. :shrug: But I’ve read your page at work before. Anyway…
rjung, I’ve never picked you as an isolationist, but it seems you do desire some form of aloofness from international affairs. But, yeah, your point is good, no sense in siding with someone who can (and desires to) kill you. But then, the US hasn’t quite done that.
Still, you make it seem like dogma; I’ve never taken the expression so seriously before, only in the context where we need our enemy to accomplish a goal against another, seperate enemy, who also happens to etc. Under these circumstances, the greater goal must succeed, and an alliance must be formed.
But, points noted. If it were dogma, it would be a pretty stupid dogma.