I'm looking for a very specific kind of argument, and I'd love some help. What I want is examples of arguments
made by conservatives (this part is important)
urging allowing government officials to engage in certain kinds of searches that would otherwise be unconstitutional
but only on condition that the results of the searches wouldn't be usable in certain kinds of proceedings (any trials, trials for offenses other than terrorism-related offenses, and the like).
Here's a hypothetical example: A conservative scholar, judge, or commentator suggests, "We ought to allow the police to engage in house-to-house searches, even without a warrant or individualized probable cause, for dirty bomb materials. True, this would normally be unconstitutional, but the courts ought to recognize a new exception from the normal Fourth Amendment probable cause / warrant requirements here. And one thing that makes the exception permissible -- "reasonable" for Fourth Amendment purposes, because it's not an excessive invasion of privacy -- is that anything the searchers find (e.g., drugs, child porn, etc.) would, by the terms of the new exception, inadmissible except in prosecutions for crimes related to the making of dirty bombs."
I'm pretty sure I've seen such examples in the past, but I'm not sure where. If any of you can help, I'd be much obliged. (I don't want to explain my purpose right now because I don't want to affect people's judgment about what to pass along. I'm also not looking for arguments about whether such exceptions would be proper or improper; for my purposes, what's important is that such exceptions had been urged.) Many thanks!