Supreme court justices are often active in the selection of new justices, advising the president as to whom he should pick.
name and explain both. potential positive benefits and a potential negative results o allowing the justices to influence the presidents choice.
An advantage is that the Supreme Court justices are the best legal scholars in the country, have held the job a long time (the average term is 26 years) and have a lot of experience with Constitutional matters. So having their advice about what new nominee is capable can be an advantage. If a President is looking for a liberal or conservative justice to take the open seat, they can get advice from those in the job already too.
I do think "cloning" the Supreme Court is a bad idea, but some consistency in judicial rulings and a respect for established law is a good thing. As the balance on the court remains roughly the same over time, we get consistent rulings on established law. It's a good thing that the interpretation of the founding document doesn't swing back and forth on a regular basis. As the President can't remove them from the bench once they are confirmed, it can be a bad thing if a Supreme Court justice has too much influence over a new choice.
The most obvious positive benefit of this would be that the justices who are already on the Court would be more likely to respect and to be able to work with the new nominee.
A second positive impact would be that Supreme Court nominees would probably be picked more on legal merit than on politics if the justices themselves had more of a say in the process.
The major negative would be that the Court would sort of tend to clone itself. There would be less likelihood of new blood (ideologically speaking) coming onto the Court.