While campaigning for the Democratic presidential nomination, Senator Robert F. Kennedy (D-NY) died from an assassin's bullet in Los Angeles, California. Senator Kennedy, former Attorney General of the U.S., was the younger brother of President John F. Kennedy and the older brother of Senator Edward M. Kennedy.  

The framers of the Constitution, meeting in closed session in Philadelphia, agreed to a plan for electing senators. Earlier proposals included selection by the president, direct popular election, or election by the House of Representatives from candidates nominated by individual state legislatures. On this day, the framers decided that each legislature would choose its state's senators--a practice that would remain in effect until the 1913 ratification of the Constitution's Seventeenth Amendment, establishing direct election of senators.

In one of the most dramatic votes in its history, the Senate mustered the necessary two-thirds majority then required to cut off debate and ended a seventy-five-day filibuster by opponents of a civil rights bill. This vote marked the first time the Senate had "invoked cloture" on civil rights legislation and cleared the way for passage of the landmark Civil Rights Act of 1964.

Ohio Republican Warren G. Harding won his party's presidential nomination on this date and went on to become the first incumbent senator to be elected president. To date, John F. Kennedy is the only other person to have moved directly from the Senate to the White House.