Congressional nominating caucus
This system was introduced in 1796 after George Washington had announced his retirement upon the end of his second term, when the Democratic-Republican Party, which had already settled for Thomas Jefferson as Presidential candidate, decided on their choice for Vice President.
The system ended in 1824 as existing political parties began to decentralize as a result of the westward expansion of America. The system had come to be known as "King Caucus", because the power that these caucuses had to nominate a president was seen as undemocratic. The failure of the caucus nominee of 1824, William Crawford, and his competitors to receive an electoral majority resulted in John Quincy Adams finally being elected president in the House of Representatives.
From 1831 onwards, the Congressional nominating caucus was replaced with national presidential nominating conventions.