Answer:
The election of 1800 was a significant event in American history, as it marked the first peaceful transition of power between political parties. The Congress had to decide the election because of a tie in the Electoral College between Thomas Jefferson and his running mate Aaron Burr, who were both Democratic-Republicans.
Under the Constitution at that time, each elector cast two votes for the presidency, with the candidate who received the most votes becoming president and the runner-up becoming vice president. However, Jefferson and Burr received an equal number of votes, leading to a deadlock.
Since the election went to the House of Representatives to break the tie, the members of Congress had to choose between Jefferson and Burr. After numerous rounds of voting, Alexander Hamilton, who was a prominent Federalist and had personal animosity towards Burr, influenced several Federalists to change their votes and support Jefferson. This decision by the Federalists ultimately led to Jefferson's victory and his subsequent presidency.
So, the members of Congress decided the election of 1800 by casting their votes and breaking the tie between Thomas Jefferson and Aaron Burr, ultimately electing Jefferson as the President of the United States.
Step-by-step explanation: