Yup Hilary Clinton and John McCaine(however u spell it) are really itching to go to war with Iran and Syria,  I'm like cough cough war mongers!  I mean the Russians are pissed off because Syria is one of Russia's last Middle Eastern allies and we gonna attack them soon this late Summer or Fall or whatever.  They already planning to send 11 warships to guard Syria,  to me thats a message to America to back off!  and still our politicians(some of em) are like yeah!  lets attack another country!  ittl only end up as a bigger conflict with more dead and deeper debt,  this time its gonna be way more difficult than Iraq or Afghanistan,  in that Iran is way more prepared than the former,  professional army well funded etc..

I spend most of the day while I'm on patrol listening to the various pundits and experts and analysts talk about these very things.
It's a knotty problem.
 
Take Afghanistan.  Everyone admits Afghanistan is a black hole into which we are pouring blood and treasure to little effect, just as other great powers have done before us.  However... They also say Afghanistan isn't about Afghanistan.  It's about Pakistan.  and Pakistan is worrysome.  It's a very fragile country, and they have a pile of nukes and a paranoid attitude; especially towards India which is a very big deal.  
Like it or not, the world is running on oil and the area in general down there is where it comes from.  Mere instability is enough to cause oil prices to shoot through the roof, and the world's economies might well be termed fragile as well....And like it or not the world's economies have powerful effects on our own.
 
We must sell our widgets somewhere, and we must buy widgets from somewhere.    
 
So, isolationism might sound very appealing, but it's not viable in todays world.  Like it or not, the world's economies are very strongly interconnected and things that might seem very isolated can affect everything.
Greece.  Who cares if Greece goes bankrupt?   Well, everyone in Europe.  Pundits tell us there is a very strong possiblility that if Greece goes under financially the Eurozone is a good bet to fail.  The already iffy economies of Europe in general might go deeply into depression and then that affects us.....
 
Letting the UN handle things.... Well, like it or not, we are the UN when it comes to military muscle.  We are the "world police" by default.   Unfortunately, someone's got to do it.    
We'd certainly like to see a little more involvement, but we have a military and defense budget that's so much greater than anyone elses that it's rather silly.   We are spending more than most all the other military powers on Earth..Combined.

too right