News journalists, do you pick the stories or do the stories pick you?

Well, not many are on the Middle East beat. So let's be a little more general.

If the reporter is assigned to a specific area, he (assume it's a man for now) is keeping an eye on matters. He makes a judgment about what is worth a story and what isn't, but then he talks to his boss -- usually some sort of editor. The two of them will talk about the situation and reach a decision. The editor does have an idea about what's going on, but more importantly he knows what is a worthwhile story or not.

Complicated stories get kicked up a ladder at times, and there are obviously some tough calls every once in a while.

To use your example, practically any reporter who is covering the Mideast wouldn't be allowed to take sides on the situation, and it wouldn't (shouldn't?) affect his viewpoint on what is news. If a pro-war reporter constantly came up with ideas supporting that position and his stories reflected that, most places would move him to another beat.