I didn't say we could determine the answer instantly, but we can most certainly determine it logically. The courts have certainly made things more difficult by inventing new meanings for various provisions in the Constitution, thereby reinforcing the notion that only they know how to divine its "true meaning", but the Constitution was written with the intention that ordinary people would be able to know what it says. Granted, "ordinary people" were considerably more literate back then, but it's still possible today for people who have an interest in the subject to understand it themselves.
I say that this is an exception under the 4'th Amendment, exactly as the 4'th Amendment says there are exceptions - it only protects you from "unreasonable" searches, not all searches.
The word "reasonable" can have absolutely no meaning in any legal sense, if there's no context to go along with it. Otherwise, we could just replace the entire Bill of Rights with "Just don't do anything unreasonable, OK?" In order for it to mean anything, it has to mean "reasonably tailored towards the attainment of a particular goal." The second half of the 4th amendment gives us an unmistakable clue as to what that goal is: investigation of a particular crime, where there's proper grounds for suspicion. You can argue all day whether a particular action is "reasonable" in some abstract sense, but if it's not reasonable within the context provided by the 4th amendment, then it's not reasonable within the meaning of the 4th amendment.
So your argument for change is "why not?" Do we seek change for change's sake now?
My argument for change is that the current policy looks very much like it conflicts with the Constitution, and that it sets (or rather perpetuates) a dangerous precedent. What exactly is your argument for "interpreting" the Constitution to allow the government to continue engaging in an activity which in all likelihood creates no measurable improvement in airline safety?
Oddly enough, the left says exactly the same thing, just before arriving at their preferred interpretation.
But that's neither here nor there, really. The key question is one of balancing competing interests. Why does your presumed 4'th Amendment right outweigh someone else's right to live?
What exactly is your argument for "interpreting" the Constitution to allow the government to continue engaging in an activity which in all likelihood creates no measurable improvement in airline safety?
How about the fact that your assertion of "no measurable improvement" is simply false? In 1961, before FAA-mandated universal passenger screening, there were four cases of hijackings on flights from US airports. From 1992-2000, after the FAA mandate in 1973, there were zero.
Why does your asserted right to be free from this search outweigh the right to life of others?