"Hope we don't have to get into some kind of war with Syria, but we have to attack targets in Syria, Iran and Pakistan if they keep war mongering in Iraq and Afghanistan."
Pot, kettle, et cetera.
"In the War on Terror, to win you have to go after every target no matter where it is, and let the police sort the bodies out."
Actually, that sounds like a really good way not to win the War on Terror. Hearts and minds anyone? Remember, if we create more bad guys than we kill, we gain nothing.
"But for Syria and Iran, the Iraq war would be over."
That's silly. Iraq turned messy because of its own internal divisions exacerbated by a few abysmal decisions from our own leadership, chief among them the disbanding of the Ba'ath government and military before we had anything to replace them, as well as rushing into national elections without establishing local political power structures. Those two events guaranteed that the Sunnis would be disenfranchised, and disenfranchised people with guns can be counted upon to make trouble. Any "foreign fighters" were entering the country along the preexisting party lines.
"But for Pakistan, the Afghanistan war would be over."
You may want to talk to the Russians and the British about that. They might have a slightly more nuanced appreciation for why wars in Afghanistan tend to last a long time.
"The Iraq war could very well have ended with the removal of Saddam, except for the foreign terrorists who came in and started a civil war by years of blowing up Shiites. There possibly, in some circles, could be an argument for decent Sunnis who weren't part of the Baathist crime organization and who mistakenly thought Saddam was good fighting the US when they invaded, but that would be the limit of the war."
After we removed the Sunnis from power and gave the reins of the country to the Shi'ites, we really should have expected what followed. Actually, knowing what was to follow, we shouldn't have taken a wrecking ball to the existing political infrastructure, but worked through it to establish a more equitable division of power. We had that chance, and we blew it. So, yeah, the war might have ended with the fall of Saddam, but it was never very likely and we ensured that it would continue past that.
I think the big philosophical problem you have is in your concept of what a nation is, and how much it matters to some people. Iraq is an imaginary line drawn by the British after the fall of the Ottoman Empire. It encircles a few distinct groups of people who never should have been in the same country together. In light of that, the idea that Sunnis in neighboring countries would come to the aid of their beleaguered Iraqi brethren is only natural, because the identity that matters more to them is not their country per se, but their ethnic and religious affiliation. Again, this is poli sci 101 stuff, and nobody should have been caught off guard when it happened.
"The fact that it spread to terrorist attacks on Shiites and then a civil war from there, is totally the fault of foreign terrorist groups and the countries that kept feeding them into the war from outside. There's no reason the Iraq war couldn't have ended in 2003, but for terrorist killers."
You really have a fetish for this "foreign fighter" idea. It's almost as intractable as your fetish for simplistic reasoning based on single causation and inability to accept situations with complex dynamics. That's going to get you into trouble someday. If you ever plan an invasion, remember to include Murphy in your war council, for his is the Law. No plan survives first contact with the enemy, and it is undignified to cry about things not going smoothly when you put yourself in a position where everything that could go wrong would do exactly that. That's why we make contingency plans and exit strategies. Those are good things.
How's this? The war shouldn't have ended in 2003, because it should never have been started in the first place. George H.W. Bush was right not to press for an invasion in 1991, because he knew exactly how messy it would be. Likewise, Dick Cheney also was right when he said that taking out Saddam wasn't worth "very damn many" additional American lives. If we wanted to effectively contain Saddam, the way to do that was through alliances with neighboring countries, particularly Iran, as well as clandestine support to potentially revolutionary elements inside of Iraq (assuming we found any worth supporting). These ties could have been formed using Afghanistan as glue, since several Middle Eastern nations have an interest in seeing that situation stabilized. Soft power should have been used almost exclusively with regard to Iraq, at least until the situation was resolved on our primary front, and under no circumstances should we have simply smashed the mechanisms of government, economy, et al like we did. That was always a recipe for disaster.
"The best thing would be if we can seal the Syrian border with Iraqi troops backed up by our air patrols."
We can't even seal our border with Mexico. That's a huge job, and the Iraqi military isn't up to it. This would really be a good time to have the bulk of Saddam's military still around, wouldn't it?
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On another note, I find it very amusing that you have such venom for nations like Iran, who may be attempting to influence events in a nation right on their border and with whom they have a long history of hostility, while you think nothing of our forces conquering nations on the other side of the planet in the name of our national interest. Who really has more of a right to be there? Don't you think Iran suffered enough at Saddam's hands to have at least some legitimate interest in Iraq?
On yet another note, the way we carried out this war really is imperial suicide. Whatever we do in terms of grand strategy, our current state of affairs cannot continue. Did you notice that China recently signed a big oil deal with Iraq? Are you aware that both our war effort and our addiction to fossil fuel is largely funded by China and their burgeoning juggernaut of an economy? I suppose the Iraqis figured there was no sense going through America to get Chinese money when they could go right to the source. And according to some, peak oil is a reality we won't be able to ignore much longer. Putting aside how much fuel the war effort is costing us (which itself might constitute a crime against our children), we really need to start worrying how eager China will be to fund our habit when the economics of scarcity kicks in and we're competing with China for this resource. But that's crazy talk. I'm sure China has only the purest of intentions in giving us all of this rope. Surely they don't actually mean for us to hang ourselves with it!
If we want to ever win the War on Terror, we're going to have to start fighting a cultural war with cultural weapons. Here are two starting points: 1) Use the mechanisms of capitalism to encourage diversification of Middle Eastern economies. 2) Use soft power and economic incentives to work towards the education and political empowerment of Middle Eastern women. Those two things, if properly implemented, would strike a far deadlier blow at Islamic extremism than any number of preemptive invasions or cross-border raids. This is not a conventional war, and we won't win using conventional weapons. I think that should be obvious to all by now.