Wealthy businessmen and affluent landowners
The Constitution states that Justices " shall hold their Offices during good behavior." This means that the Justices hold office as long as they choose and can only be removed from office by impeachment.
That is was the key stone to their life and they needed to protect it at with everything they had to offer,
United States - wanted to establish lasting peace in Europe
Germany - wanted a treaty based on the armistice it had signed
Italy - wanted territories near the Adriatic that Britain had earlier promised
France - wanted to punish and weaken Germany