I know a lot of history of Dr.King himself. When he said let 'Let freedom ring" he's using Anaphora.
After being passed by both houses of Congress, a constitutional amendment must still be passed by 3/4ths of the states. After it is passed by Congress and the states, it still must be approved by the US President. This is because the president has the power to veto any law passed by Congress. If the president vetoes (stops it from becoming a law) the amendment, the veto can be overrode by another vote in Congress.
In 1800, however, Jefferson won the presidential election with 73 votes to Adams's 65, but the Republican vice presidential candidate Aaron Burr also received 73 votes, making the vote for the presidency a tie. In case of a tie, the Constitution directed that the election be decided by the House of Representatives.
