What was Carlo thinking?

The gunmen just happens to be waiting at the toll booth when Sonny is racing to his sister? That story wouldn't fool a Corleone or even the kid who takes care of the shopping carts at the Acme.

Of course it wouldn't fool anyone. But a major subtheme of the Trilogy is how people underestimate each other and make fatal mistakes. Carlo thirsted for revenge for Sonny's public beating and humiliation of him. Whatever Tattaglia or Barzini promised him for setting up Sonny was almost irrelevant: here was a chance to get revenge. In that moment he was blind to the consequences of such an obvious move. Ditto Paulie Gatto: he let his greed blind him to the fact that Sonny and Tom had to know that he'd be a prime suspect in setting up Vito for the shooting outside the Genco offices. He, like Carlo, paid the price. As Vito said later: "Women and children can be careless, but not men."

Since Carlo was so obviously behind Sonny's murder, why didn't Vito have him killed? Many of us here believe that Vito couldn't bring himself to kill his daughter's husband. And Vito, confronted with Sonny's death and the urgent need to bring Michael back from Sicily, decided that "this war ends now." It was not a time for more bloodshed. He needed to appear weak and humble, the better to lull his enemies. Besides, he knew Michael would take the revenge on Carlo that he couldn't bring himself to act on.

I disagree I think it is a flaw in the storyline. Carlo is part of the family he lives and works with the Corleones. He knows what they are capable of. Why would he go on a suicide mission to get his revenge? His roll in Sonny's death is painfully obvious and he does not even have the sense to leave town!He continues to hang around the Coleones.Barzini etc could promise him anything but what good is it if your dead?I can go along with the Paulie explaination but the Carlo thing is just too much of a stretch.

I am not convinced either. To time it all correctly is quite a bit of stretch. Carlo beating up Connie knowing that she would call Sonny, who would start immediately and drive without his gunmen and pass through that particular tollbooth Lazy script-writing maybe

TB, you hit it on the head. To properly interpret the movie, we are forced to remember the novel's content. In it Vito told Michael that he probably didn't have the heart anymore to do what had to be done and that's why he was retiring. Vito ended the war, period. He had formulated a long range plan for revenge and murdering Carlo would have tipped his hand. That Carlo would smack around the daughter of a Don is sufficient indication that he was quite a stupid person. That he allied himself with Barzini is a gamble, at best. So, it's no surprise that he didn't appreciate the threat to his life if he played a part in Sonny's death.

And Henry, I'm not sure why you find it to be such a mystery why the gunmen were waiting at the tollbooth. That's what they were instructed to do.

Oliver:I am not surprised that there were gunman in the tollbooth. My point is that Carlo's role in the killing is so obvious that I do not belive it credable that he thought he could survive this plot.To accept the storyline you must believe that Carlo is so venegful that he is willing to die to get even. It's a powerful series of scences but I don't find it believeable.

Henry, I see what you're saying. But, while it may have been foolish on Carlo's part, I don't think it is that difficult to believe.

Sonny had a hundred buttonmen looking for Sollozzo. Maybe Tattaglia had a hundred buttonmen looking for Sonny. Maybe they began to tail the car after it left the compound and only pounced when Sonny stopped to pay the toll. Who would know the difference once Sonny was dead? Carlo may have believed that there were enough possibilities like that to give him some cover.

Plus, there were other motivators for Carlo. He realized that the Corleones would never give him anything important. Plus, he surely wanted revenge for Sonny's public beatdown of him.

The point is that people who are obsessed with vengeance or greed do stupid things that lead them to their deaths. As Vito said in the novel, "Revenge is a dish best eaten cold."

Exactly!

Carlo had just suffered a lengthy and intensely humiliating public beating at the hands of his brother-in-law. He wanted revenge and he wasn't thinking beyond that.

It is a bit of a stretch to think he would hang around afterwards but then again he probably hadn't thought things through that far. Maybe he thought being married to Connie would give him a pass if things came to a head...

I agree. Also, we must not forget that Carlo was a fool. I mean, he even started fighting with Connie in Vito's house (deleted scene). He was having affairs, he ruined the business he was given by the Corleones.
And even before the beating he was humiliated in front of the Corleone family members. He had to sit in the kitchen with the women while the Corleones were talking business with Vito. Sonny humiliated him at the table (probably not the first time).

TB : In the novel I hope Vito acknowledged the Cereventes when he made his "cold revenge" statement. It was Cerveventes who said "revenge is a dish best served cold".

I didn't know that. Interesting.

I haven't read Don Quixote but it is apparently the source for many common expressions, including "the sky's the limit," "there's no love lost between them," and "give the devil his due."

Amazing that something not even written in English could have such an impact on the language hundreds of years later.

Not to mention the derivative saying, "tilting at windmills."

And the word "quixotic." But the amount of coined expressions, especially, is unbelievable.

No it didn't. It originated with Kahn in Star Trek II.