Captain, are you entirely certain which side you're on?
5 seconds sound clip from the Casablanca (1942) movie soundboard.
You can hear this line at 01:03:21 in the Blu-ray version of the movie.
Quote context
[...]
- Arrêtez, je vous en prie! Je vous en prie, arrêtez!
- I don't like disturbances in my place. Either lay off politics or get out.
- You see, captain? The situation is not as much under control as you believe.
- Captain, are you entirely certain which side you're on?
- I have no conviction, if that's what you mean.
- I blow with the wind and the prevailing wind happens to be from Vichy.
- Surely the Reich doesn't admit that possibility?
[...]