The weakest go to the wall proverbial saying, early 16th century; usually said to derive from the installation of seating around the walls in churches of the later Middle Ages. Go to the wall in figurative use means, succumb in a conflict or struggle.
the weakest link the point at which a system, sequence, or organization is most vulnerable; the least dependable element or member.
In the televison game-show The Weakest Link (2000– ), contestants who have been voted off are dismissed with the words, ‘You are the weakest link…goodbye.’
See also a chain is no stronger than its weakest link, weaker.