Well, rounding "them" all up without cause is one approach. The problem I find with that theory is you alienate our best sources of intelligence concerning domestic terrorism, both citizen and non-citizen, by not giving them any recourse.
Example being, you have a guy who probably isn't the biggest fan of America living here, he attends a pretty radical Mosque with these guys who invited them into their group which is connected to Al Qaeda. While our subject isn't a fan of US foreign policy he's not down with smoking a bunch of innocent civilians.
This could go one of two ways: The US roles every Muslim looking person up and throws them into holding. Now this guy who's on the fence is away from his family and pissed. The other way this goes is he doesn't get wrapped up and starts talking yielding valuable intelligence that allows us to paint the big picture and spread a wider but more accurate net.
Oh, and the problem with profiling is that our enemies adapt. It's the signature block for terrorists. We figure out how the do something so they change the way they do it. Look at Al Qaeda in Iraq recently. We got really good at identifying suicide bombers. I won't say how we did. But what did they do? Start using women and the retarded. As distasteful as it is, it's effective. Now, you start profiling every Arab-looking person that enters an airport, what do you think Al Qaeda will do?
Of course, what do I know?
