Redefining what a presidential term is probably my least favorite reform of the government but it's probably a tradition worth breaking. I like how it neatly works out every four years since electors cast their unanimous choice for George Washington in 1788 and with the exception of death (natural or by the assassin's bullet) or resignation every four years the voice of the People would be made clear, not always crystal clear.
But if the definition of what a term length is should be changed to six and limit the person to one term. Or they cannot run for consecutive office. That throws the opportunities for more Grover Clevelands, non-consecutive 2-termer. Presidents have suggested this change since they feel they enter office with reelection on their mind and not governing. The president of Mexico serves a single six year-term.
Traditionally, meaning starting with Washington, after serving two terms, a president stepped down from power. Thomas Jefferson, the second president to serve a second four year term, followed Washington's lead in 1808 and so did all those that followed. There's an UNTIL coming. Ulysses S. Grant pondered a third non-consecutive term in 1880 but the Republican Party chose dark horse and became the last incumbent member of the House of Representatives, so far, to win the presidency, James A. Garfield. The Democratic Party briefly considered Grover Cleveland for another non-consecutive term in 1900. Theodore Roosevelt considered breaking his promise of not running for another term in 1908 (TR considered William McKinley's second term 1901-1905 as his first term since it was only 6 months old when he became the 26th POTUS) but put his 3rd term plans off until 1912 when he came in second to Woodrow Wilson and ahead of the incumbent, William Howard Taft. 1912 was the last time a third party placed second in both popular and electoral votes. Twenty years later Franklin Roosevelt would come into office in March of 1933 with such hope and optimism that happy days were really here again.
FDR won reelection in 1936 and expected that to be it. He too would do what all the other two termers before him, give up power and build a library. Well, the library thing was something new. But the threat of Adolf Hitler and war in Europe worried FDR. Roosevelt 32 thought the isolationists would get someone elected and keep the United States from interfering in a foreign war and he knew of no Democrat that he could trust to maintain the New Deal programs. So while some opposed the idea of FDR seeking a third consecutive term, he still won a nice majority in both popular and electoral votes. The People spoke. He came in with a new vice president, Henry A. Wallace, a progressive and liberal from Iowa replacing the two term VPOTUS John N. Garner, a conservative Texan that wasn't a fan of FDR running again for a third term but also the New Deal, which equals big government.
Roosevelt 32 would of course go for a fourth term. Just like there was in 1940, there was opposition to a 4th term but still the People spoke and FDR was off to a 4th term. Had FDR lived his term would have ended on January 20, 1949. There is no evidence that FDR would've run a 5th time. It is rather believed that FDR would've been the first to resign the presidency once the war was over, but I guess he would want a better outcome than a 44 year cold war. But he died a little over 2 months into his historic 4th term and the successor president was a new vice president. Part of FDR's fourth nomination, the Democratic Party replaced the left leaning Wallace with a more moderate choice in Missouri's Senator Harry S. Truman, who led hearings into military spending during the war. President Truman would follow in the footsteps of the other 20th Century VPOTUS turned POTUS before him and win a term as president in his own right in 1948. He could've tried again in 1952 if he wanted. The idea that someone had the freedom to run as many times as they wanted appalled the opposition.
Truman stepped aside when he saw there was a serious challenge within his own party. But the next person to serve in the Oval Office would be limited to two terms. Jealous of the monopoly held by a single individual and thus a political party on the presidency did not sit well with the other minority party. The People knew FDR was breaking with tradition and if they disagreed they would have chosen someone else and same with the party that nominated him a third time before the entire country voted of course. The Republicans were successfully able to amend the Constitution in 1947 (Ratified in 1951) in the brief moment they controlled the Congress limiting the term of a president to 2 and the years in office 8-10. The amend did not apply to the current office holder. Truman could pull a Roosevelt 32 and run forever!!! But he didn't.
Dwight Eisenhower was limited by the new Amendment and wished he could have the opportunity to serve the people another four years...if that is what they wanted, he was down. John F. Kennedy tragically did not get to see reelection but all bets were he was cruising to a comfortable reelection in 1964. Lyndon B. Johnson won a landslide in '64, as a vice president turned president. But now the 22nd Amendment was in effect.
LBJ finished the remainder of Kennedy's first term November 22, 1963-January 20, 1965, just a little over a year. That means Johnson 36 could've ran for another term in 1968 and his announcement of not running seeking or accepting the nomination was a shock because it was expected since he could run. Since he only served a little over a year as POTUS before his first full term, LBJ could've served until January 20, 1973. But Vietnam did him in.
The shock of LBJ not seeking another term is because it is expected that a president would seek reelection. James K. Polk kept his word and served one term. Rutherford B. Hayes did too, although he came into office with having lost the popular vote and winning electoral votes chosen by a committee because the Congress was too wimpy to follow the Constitution and they themselves vote like in 1800 and 1824. I remember John McCain's campaign in 2008 considering the idea of saying he'd serve a single term, but that announcement, while great, makes the new president a lame-duck as they become in the second term under a 22nd Amendment.
Another what if within a what if is if Gerald Ford won the 1976 election he would not be able to run (or at least complete a term since it would end in 1985 and that would be a year more than the Constitution allows under the 22nd Amendment). So Ford would probably not run in 1980 but if he was super popular could've and resigned once he reached the maximum number of years allowed. Or he could've challenged the Amendment by staying in office and not running again in 1984, sort of like Mayor Michael Bloomberg of New York City from 2002-2013.
But if the country were to amend the Constitution to switch to a six year presidential term, there would be no more constant electioneering, presidents could focus on the job and if they wanted could seek the office again after having been out of power for six years, always knowing that you'll never have to challenge the incumbent. A huge downside is of course we are stuck with that POTUS for SIX whole years as opposed to the every-four years of getting to switch him (or her) out...just have to wait an extra two years.