Where do you draw the line?

So this port deal thing has gotten me thinking, and I asked Charlie (my co-worker) about his views on the matter. I will attempt to recreate the conversation that just took place.

"So Charlie, whaddya think of the whole port deal thing?"

"Uhh.. "

*swivels chair towards me*

"Well, apparently the ports were under the control of a British company and then they were acquired by an Arab company."

Just a note, I'm not sure if it happened like above but the basic idea is the same.

"So what do you think about it?"

"Well, I think it they should have thought a bit more about it before trying to put this deal through. I mean, even though they are an ally, you can never be too careful.. I just think its a bad idea"

I continue to stare at him, and as expected, he begins to talk again.

"I mean, people say you shouldn't profile, but thats a bunch of crap."

At this point he throw the curveball.

"Did you know most serial killers are white males?"

".. .Uh. . .no"

"Yeah most serial killers are white males, mid 30s."

I see the point he was trying to make, but man sometimes he creeps me out.

So then I asked him where you draw the line. He says you don't draw a line, you "do what you have to do to protect the country."

I'm all for protecting the US and all that but I constantly try to figure out just where that invisible line is. How far are we willing to go to ensure domestic security?