Muslims

[Wyrd of Gawd]

It keeps happening because of the root of the problem: the fact that there is no order in Islam

There is no order in xtianity, either, but finally they did stop.

Complex problems do not have simple solutions.  That, right there, is the fundamental problem of American foreign policy as practiced since about 1900.

You know, if we stop selling them arms they would have to finish their war with sticks and swords.  How very koranic! 

Finally,

I don't think it's right for us, as the richest and most powerful country in the world

You need to lose that idea.  We are the most indebted nation in the world precisely because we have been trying to do exactly what you are suggesting.  And military power has not proven to be terribly effective.

You really need to ask yourself how it is that ISIS can take 1,000 assholes, give them a swing across the monkey bars, hand them an AK-47 and send them out to chase 30,000 well-equipped Iraqi "soldiers" out of Mosul in an afternoon?  All this shit about "training" rebels is exactly that.  Shit.  It's a panacea.  Commitment to a cause is what matters.  You need to understand that we always back the wrong horse.  You also need to understand that we are bankrupting ourselves trying to occupy the whole world.

Americans always think that training and education will solve all problems.  Sometimes whacking the idiot upside his head with a club is more effective.

Speaking of Mosul, Saud conquered Riyadh with just 40 men.  https://en.wikipedia.org/wiki/Ibn_Saud
How few will it take to conquer Paris and Berlin?