I'm not talking about feasibility. If you want to argue that Iraq was the most "feasible" country to invade, I'd argue that feasibility is a poor reason to invade a country.
The problem with arguing that we need to eliminate Saddam NOW@!~@$%#@@ is that then, you have to get into why in the hell it was Saddam and not, say, the Saudi Royal family or Castro or whichever other dictators there are out there. The fact that you simply repeat "BUT WHY WOULDN'T WE GET RID OF SADDAM!?!" after I make that argument doesn't change the fact that, quite obviously, it wasn't urgent that we rush into Iraq just so we can get rid of a HORRIBLE DIRCATRO when there's quite a few other ones that we tolerate.