Was Robert F. Kennedy assassinated because of his brother?

It is hard
to say exactly why Robert F. Kennedy was assassinated given that Sirhan Sirhan clearly had
serious psychological problems.  However, there is a way of arguing that Kennedys assassination
was indirectly connected to the fact that his brother had been a very famous
president.

In one sense, RFKs assassination was not connected to his
brother.  Sirhan was supposedly motivated by RFKs support of...