"the buck stops here"

[Sergio]

What is that suppose to mean?

[incitatus]

It means that the ultimate responsibility for whatever is being discussed rests with the person making the statement

[homer]

President Truman had a wooden sign displaying the phrase on his desk at the White House. It was made by prisoners at an Oklahoma jail. It derives from 'pass the buck' which means passing the blame or responsibility to someone else. That expression came from the Wild West days when a knife with a buckhorn handle was used to indicate whose turn it was to deal in a game of poker. If a player didn't want to deal he could 'pass the buck'.