The X-Files, Season 8

Mulder:
You told me that he told you he knew how to stop Billy Miles. Are you telling me now that you think he's a liar?

Doggett:
He is or he isn't. What the hell difference does it really make?

Mulder:
It doesn't make any difference at all. Unless you want to protect Scully and that baby.

Doggett:
And then what? How long can you keep this up? How long until the next Billy Miles rears his head? The next threat? The next phantom? You ever stop to ask yourself? (Mulder looks a little uncomfortable) All the sacrifice, the blood spilled - you've given nearly a decade of your life. Where the hell is it all going to end?

Mulder:
(thinks for a moment; softly) I don't know. Maybe it doesn't.