So, we are familiar with the concept of preventive war or preemptive strikes, where we attack someone so that they can't attack us, such as the invasion of Iraq. The premise is that they will hurt us in some way in the future, so we need to ensure that they can't.
Why is it we can attack another nation and kill thousands of people in the name of preventive maintenance but we can't arrest someone who we believe is going to commit a crime (say murder or a bank robbery)? Why do we generally have to catch them in the act (or soon after), have a trial and then convict them? Does an individual in the United States have more rights than a sovereign nation in the eyes of the authorities?
Perhaps we should start arresting people and holding them in prison until they admit that they were intending to commit the crime for which we arrested them. Then we can charge them, convict them, and send them to jail. It would cut down on actual harm caused, because the crime will never have been committed. People won't have been murdered, houses not broken into, banks not robbed. Insurance money would be saved.
And think of ease of conviction. We don't have to prove that the crime happened and that this individual committed it, because there was no crime! All we have to show is that the person intended the crime to occur, and that can be anything as simple as a passing thought. Court costs would be tremendously minimized, saving more money. We could streamline the system.
One small problem is with the field of illegal immigration, since the criminals then aren't typically in the country before they become illegal immigrants. This means that we'd have to be able to enter other countries where the illegal immigrants live and arrest them before they think of entering illegally. Unfortunately, the Supreme Court seems to think that the writ of habeas corpus applies to everyone, not just good old fashioned americans, so they'd have to be given court time, but I think the convictions would be pretty easy, especially if the Republicans get their way and illegal immigration does become a felony. All the proof we'd need is that they'd rather be in America, and since America is the land of the free and better than every other country, who wouldn't want to be here instead of where they currently are? Bam! Guilty. No more illegal immigration.
Of course, then again, sometimes, perhaps people consider breaking a law and then change their mind before they actually go through with it. It doesn't seem quite fair to hold them responsible for passing thoughts, or for NOT breaking the law. Perhaps the current system is ok.
Maybe preemptive strikes against countries with whom we're not at war aren't right, either?