[/QUOTE]There has been some discussion here in the past as to exactly what The Turk meant by this statement.

I am of the mind that he was referring to the fact that it was Don C's defenses and regard for his personal safety that was slipping.

I think it was implicit that Sollozo would have had to clear the assassination attempt with the other heads of the five families before he acted. The murder attempt on Vito Corleone would have been something that was unthinkable unless there was an agreement from the very top (Note in GFII how Michael, albeit using a ruse, asks Roth's permission to whack Pentangeli). Also note that later in the movie Barzini is walking up a flight of stairs into a building with NO body guard. This is cause he thought they were in a peacetime situation, as did Vito Corleone when he went to get the fruit.