In order to prevent something from taking place, the use of the data by definition would have to include searching for evidence of crimes that have not yet taken place.

I disagree. We're getting down into enough detail now that it becomes necessary to clarify what we mean when we say things like "suspicionless investigation of our papers and effects."

If my data sits in a database and is never actually looked at, can you say I have been subject to "suspicionless investigation of my papers and effects?"

What if my data sits in a database that is searched for certain keywords. Say, the last name of a known terrorist operating Alergia. But since I have no connection to him, none of my records are flagged for follow-up. No human has looked at any of my information, but a computer scanned my records along with all the others when it was being searched for the terrorist's name. In this case, have I been subject to "suspicionless investigation of my papers and effects?"

If you say "yes," then you would at least admit, I think, having a database of billions of electronic records scanned by a computer constitutes a kind of search that the authors of the Constitution could never have imagined or considered.

Here's the real problem: When you say the government is conducting "suspicionless investigation" of you and your effects, people think you mean they are reading your email, monitoring your online activity, and listening to your phone calls. There are tens of millions of Americans who now think, thanks to a combination of malicious reporting and genuine confusion, that everything they do online is being actively monitored. But it's not.