probable cause.......
Is our Constitutional protection against unreasonable search and seizure, and if you would care to read the Fourth Amendment to that Constitution you might note there would be a high bar before any judge would sign off on a warrant for a congressman's office while congress is in session.
And please note the ensuing search probably damns any case Justice might have, inasmuch as evidence seized would be considered to be fruit of the poisoned tree and not admissible at trial.
After all, your congressman would have to be tried before one of those liberal judges you are so fond of railing about.
Publius