People have to look at themselves if they are to figure out the cause of the riots of 1992 - it was not just police brutality, though that was the flash point. People have to look into how they treat other people. The US could not prevent it by force, but by difference in attitude - on all ends.
Riots by their very definition are lawless outbursts. Although the LA Riots were a grave tragedy and, in a perfect world, they would not have happened, the government cannot legally prevent protests. The people rose up against racism, and they were right to do so. Sometimes, violence is justified for a cause.
No, America should not have been able to prevent the 1992 Los Angeles riots, because not all conflict can be prevented. There was not a lot of lead up to the 1992 Los Angeles riots, and the police cannot be in every place to prevent all things before it happens. They do not have a crystal ball.
I don't think America could have prevented the LA riots in 1992 unless they change the outcomes of history. I do think the way the riots were handled was poor and led to more rioting. I think they should have been more prepared and if they handled situation better would have been okay.
I don't think America was prepared for the riots. Should we have been more prepared? maybe. I don't think we could have been able to stop them though. I do think we learned from them and now if an event like that comes again we will be more prepared to handle it.