How we cite our quotes: All quotations are from Taxi Driver.
Quote #4
TRAVIS: The idea had been growing in my brain for some time. True force. All the king's men cannot put it back together again.
The "king's men" won't be able to put anything back together again because Travis will smash things so thoroughly by killing Palantine (which he doesn't actually do, in the end). There's no moral purpose to his action at all—he wants to kill a presumed "man of the people" purely out of hate and rage. He holds all of America and all of humanity in condemnation.
Quote #5
ANDY: There you go—a supreme high re-sale weapon. Look at that. Look at that. That's a beauty. I could sell those guns to some jungle bunny in Harlem for five hundred bucks. But I just deal high-quality goods to the right people. How about that? This might be a little too big for practical purposes in which case for you, I'd recommend .38 snub nose. Look at this. Look at it. That's a beautiful little gun. It's nickel-plated, snub nose, otherwise the same as the service revolver. That'll stop anything that moves. The Magnum—they use that in Africa for killin' elephants. That .38—it's a fine gun. Some of these guns are like toys. That .38—you go out and hammer nails with it all day, come back and it will cut dead center on target every time. It's got a really nice action to it and a heck of a whallop. You interested in a automatic? It's a Colt .25 Automatic. It's a nice little gun. It's a beautiful little gun. It holds six shots in the clip, one shot in the chamber, if you're dumb enough to put a round in the chamber. Here, look at this. 380 Walther, holds eight shots in the clip. That's a nice gun. Now that's a beautiful little gun. Look at that. During World War II, they used this gun to replace the P38. Just given out to officers. Ain't that a little honey?
The illegal gun dealer, Easy Andy, clearly relishes guns—and uses more than a little racism in his sales pitch, besides. It's clear that he doesn't care what Travis does with these guns—he's not interested in the moral consequences of selling illegal firearms.
Quote #6
TRAVIS: Listen you f***ers, you screwheads. Here's a man who would not take it anymore. Who would not let—listen you f***ers, you screwheads. Here is a man who would not take it anymore. A man who stood up against the scum, the c***s, the dogs, the filth, the s***. Here is someone who stood up. Here is... [draws gun]. You're dead.
Travis is rehearsing his angry message to the world, trying to stylize his intended murders as an act of heroic resistance to a corrupt humanity. This is one of the points in the movie when we realize how crazy he really is.