Good question, terrible answer. What do you think?

Ethically there is never going to a be good answer. Criminals are generally a product their cultural background and environmental upbringing. People do what they're conditioned to do and what they feel is necessary to survive. Breaking that mould is incredibly difficult. Extremist beliefs can be scary. They have an entire different set of psychological filters through which they see the world to us. Communicating in a manner that you are going to be understood is always going to be incredibly difficult.

In politics there are decisions. Sometimes bad decisions have good outcomes, sometimes good decisions have bad outcomes. At best, all anyone can do is make the best possible decision based on the limited information available to them and then hope for the best. The perfect decision may still end up in absolute sht. Hence why it's very difficult to accurate proportion blame to something. Then to compound the problem people don't care about reality they only care about their perception of it. We as humans are conditioned to be more extreme in our perceptions of, well, everything. Extremist ideologies spread faster than moderate ones simply because that's way of our nature.

Putting decisions together with communicating you always have a recipe for disaster. It'd be nice if we could communicate effectively with other humans and decide our fates mutually, but we can't. There are groups of people that would happily tear down the fabric of our society to impose their own visions of it on us. How do you deal with these people?

First, you have to assess whether your own survival is worth whatever ethical sacrifices you are willing to make. From my own belief, cleansing an extremist ideology as Harris postulated makes us no better than them. It's not worth surviving if we don't have the values that we're currently surviving with. Quality and way of life is everything to me.

You also have to assess whether's it's possible for you to enter into constructive relations with these other people. Taking crime as an example, we could just isolate communities rife with crime or we could proactively engage in trying to reduce the sociological factors that produce crime in the first place. Obviously for a group like ISIS this is intrinsically more complicated. Maybe I'm incredibly naive and romantic but I believe we should still try. Humans can't learn empathy unless they witness other examples of it. Dropping bombs and scaring the sht out of people generally is only going to fuel one thing: bloodlust. But there still comes a point when you gotta be realistic. If ISIS got control of the world's nuclear arsenals. I'd happily be the ones to let them fire on us first rather than a preemptive defensive strike. Not because I don't think our survival is worth is, but precisely because I believe our way of living to be totally worth it. That's just my belief though others I presume would value some means of survival more and the question to ask is how selfish am I in giving this opinion? That I would stake all my values over the lives of everyone in my society. Their opinions matter too and they might not be so willing with death instead of a different way of life. It might be that a pre-emptive strike is the only to guarantee their survival.

Hence, why there is no good answer.

The key word in your post is 'bid'.

So western companies (or, perhaps, just American?) should not be allowed bid for contracts in Iraq?

Prior to 2003 western companies were indeed shut out, but sanctions were in place.

Not many countries in the world can exploit their oil/gas resources without any foreign expertise. Saudi Arabia is full of western contractors, for instance. Things could be kept ticking over to some extent in the short to medium term without them, but in the longer run production and revenues will decline.

Just what is your point? The Iraqi government cannot exploit its resources using domestic expertise alone. The Irish government can't either.