Usage example with a context:
She has given a full and exhaustive account of her last hours with Boris," Prokhorov said. "If any further investigative action is required, she has promised—something she has done publicly—that she will cooperate. The main thing is that the guilty parties be tracked down
I would like to ask native speakers of English what kind of feel do you have when you hear a sentence that uses the subjunctive mood? What do you think the difference semantically as well as in meaning would be if we changed the above sentence to something like this: the main thing is that the guilty parties must be tracked down?