Caro has an amazingly concise, illuminating and entertaining history of the senate in the first section of "Master of the Senate". A primary suspect in the institution's less than stellar performance in the first decades ofthe 20th century was the seniority system:
Democrat Carter Glass had ascended to the Chairmanship of the Appropriations Committee in 1932, when he was seventy-four. During the 1940s, Glass was very ill - had been very ill for years, sequestered in a suite of the Mayflower Hotel that always had a guard at the door. He had not even appeared on Capital Hill since 1942. By 1945, there were even suggestions that perhaps Glass, then eighty-seven, should resign. But, as Drury reported, "from the guarded suite...through whose doors no outsider has passed in many months to see whhat lies within, has come the usual answer. Mrs. Glass has replied for the Senator. The suggestion will not be considered." In Glass' temporary absence, the seventy-seven-year-old McKellar presided over Appropriations. "In his day", Allen Drury wrote, "Old Mack from Tennessee had been the most powerful and the most ruthless man in the senate", but that day was drawing to a close. More and more frequently during the 1940s, after he had been presiding over a committee meeting for hours, he would pound the gavel to signal the session to begin. (McKellar was sensitive about his age. Once he was politely asked in a Senate corridor, "How are you today, Senator?" As Russell Baker relates, "In reply, the old man, interpreting the words as a reflection on his failing health, raised his cane, thwacked it angrily against the fellow's collarbone, and passed on without a word."
The indispensible Wikipedia adds the following connection:
In 1952 McKellar stood for a seventh term, despite being by then quite elderly (age 83). He was opposed for renomination by Middle Tennessee Congressman Albert Gore. McKellar's reelection slogan was "Thinking Feller? Vote McKellar.", which Gore countered with "Think Some More – Vote for Gore." Gore defeated McKellar for the Democratic nomination in August in what was widely regarded as something of an upset.
I haven't read the meat of the book yet, but I have a feeling this crotchety old men's club is about to get shakin' and stirred by a certain young dynamo that you really can't help but feel drawn to.