Smallville

Season 9 Episode 16 "Checkmate"

Amanda Waller: I have reason to believe there are aliens among us. They have designs much bigger than just getting green cards. I need your help.

Clark Kent: To do what? Chase down rumors and UFO stories?

Amanda Waller: What if I have proof? Actual alien blood. The keystone to World War III.

Clark Kent: Maybe these aliens aren't here to start a war.

Amanda Waller: If you don't stand with us, you stand against us. It's time for you to pick a side.

https://www.imdb.com/title/tt1588125/quotes/qt1486309