Character Analysis
For most of this movie, we're led to believe (like Lt. Snyder) that Polk is an FBI agent who wants to take down Henry Gondorff. And for most of this movie, we're led to believe (like Lt. Snyder) that Johnny Hooker is the man he wants to help him do it.
When he first meets Hooker, Polk blackmails Johnny into betraying Henry by threatening to lock up the family of Luther Coleman. He ends the discussion by telling Johnny:
POLK: All right, Hooker, but you take it on the lam, and we'll shoot you down on sight.
He adds to Lt. Snyder that,
POLK: We just got a tip that Gondorff's mark is some big New York wheel. As soon as we're inside, you get him out of there fast before the reporters show up.
In many ways, Polk/Hickey is the linchpin that holds the entire scheme of this movie together. After all, he's the one who makes sure that both Snyder and Lonnegan think that Henry and Johnny have been killed.
Henry rightfully congratulates Hickey on the job he's done, and Hickey happily answers by saying:
POLK: No problem, Henry. Snyder went for it all the way. You shoulda seen the rag he lit under Lonnegan.
You've got to hand it to Hickey for being such a good conman. After all, he ends up conning not only Snyder and Lonnegan, but also most of the movie's audience.