Only party I'll be smiling at is the one that sees you at the end of a rope.

5 seconds sound clip from the Back to the Future Part III movie soundboard.

You can hear this line at 00:55:49.396 in the DVD version of the movie.

Quote context

[...]

- Just like you, Tannen, I take every advantage I can get.

- Now you gonna check your iron?

- I was just joking with your deputy. Of course, I'm gonna check my iron. We all were. Weren't we, boys?

- Yeah, right!

- Tannen. Your knife, too.

(Knife hitting wood)

- Smile, Marshal. After all, this is a party.

- Only party I'll be smiling at is the one that sees you at the end of a rope.

- Have fun!

- See, that's how you handle them, Son. Never give them an inch, and maintain discipline at all times. Remember that word, discipline.

- I will, Pa.

- Why, Mr. Eastwood, nice to see you.

- I see you got yourself some respectable clothes, lad, and a fine hat.

[...]