Until 1977, senators of both parties took turns presiding over the Senate. That practice ended, however, in the wake of trouble during the summer of 1975. With Democrats enjoying a numerical advantage over Republicans of 62 to 38, Majority Leader Mike Mansfield sought recognition to proceed to the consideration of a 1965 Voting Rights Act extension. Immediately, he ran into opposition from two southern senators. North Carolina Republican Jesse Helms, who occupied the chair, ignored Mansfield, thereby disregarding a 40-year-old precedent supporting priority recognition for party floor leaders. Instead, he recognized Alabama's James Allen, a master of Senate delaying procedures.
Mansfield responded in a cold fury, shouting, "What has happened to comity in this chamber?" With the assistance of Senate Whip Robert C. Byrd, Mansfield recessed the Senate until Helms' rotation expired. Months later, when Senator Byrd became majority leader, he instituted the practice of employing majority-only presiding officers.
For at least 10 years prior to this 1975 incident, Senate party officials had experienced difficulty in recruiting temporary presiding officers for late-afternoon and evening sessions. During the 1960s, Oregon Senator Wayne Morse frequently took the floor, just as others were thinking of calling it a day, to attack President Lyndon Johnson's policies on Vietnam. Dubbed by floor staff "the five o'clock shadow," Morse often continued his remarks well beyond dinnertime.
This situation came to a dramatic turn on the summer evening of July 15, 1965. Shortly after 7 p.m., Senator Morse stood ready to begin an extended address. In the chair was Maryland Senator Daniel Brewster. Brewster recognized Morse. Morse then briefly yielded to another senator. Earlier, Brewster had warned party floor aides that they had better find a replacement, because he absolutely had to leave when his shift expired at 7 p.m. to meet his wife. By 7:15, as the other senator finished speaking, and with Senator Morse waiting to reclaim the floor, Brewster looked around the Chamber. Seeing no replacement, he abruptly adjourned the Senate. Morse erupted.
The following day, Senator Brewster delivered an effusive apology to a mollified Morse. This prompted Majority Leader Mansfield to praise both senators as "big men, with a capital B."
That evening, which happened to be a Friday, life in the Senate returned to normal. Floor staff observed just two members in the chamber: Morse on his feet and Assistant Majority Leader Russell Long dutifully presiding for as long as Morse wished to continue.