The Reagan Range

When a timeline features Ronald Reagan elected President before or (very rarely) after 1980, the Reagan Range—the long interval of years during which Reagan could plausibly have won the Presidency—is at work.
Ronald Reagan was among the most influential Presidents in United States history, and arguably the most influential of the late twentieth century. Reagan's legacy continues to reverberate throughout the American political scene, his words and policies continuing to dominate much of American conservative thought.
That said, he was also quite old—in fact, upon his election in 1980, he was the oldest President ever elected in the country's history (a record he would later lose to Donald Trump in 2016, though as of 2018 Reagan is still the oldest ever to have held the office, aged 77 at the end of his second term). His political career began in 1967, when he was first elected Governor of California, and he sought the Republican Presidential nomination twice, in 1968 and in 1976, before finally winning it in 1980. This has led to many questions: what if Ronald Reagan had been elected President earlier? Behold, the Reagan Range.
Without a pre-1967 PoD, the Reagan Range can comfortably stretch back to 1968, given his unsuccessful bid for the GOP nomination that year. It can also be plausible to get Reagan into the White House in 1964, though that would require an early PoD (not only to alter Reagan's career path, but to change political circumstances in such a way that a hardline Republican can win in that year). Before 1962, Reagan was a political liberal who identified with the Democratic Party; a Democratic President Reagan before 1964 is a seldom-explored, but potentially entertaining idea that would nevertheless require a lot of tweaking in the early 20th century (not least because it would be difficult getting him elected governor of a state that elected exactly one Democratic governor between 1899 and 1959). The very earliest presidential election in which Reagan would have been able to run was 1948, but getting him into the White House then is very unlikely, not least because the public would not have wanted to vote for such a young man who had never held political office.
As for having him elected after 1980, it seems a stretch. The public voted for a 73-year-old in 1984 because they overwhelmingly approved of his performance in office, but as a newcomer in that year, he would probably have alienated voters because of his advanced age. 1988 is quite unlikely—the idea of a man in his 80s holding the nuclear codes would freak out most Americans, and . And 1992 is essentially implausible—even though he wasn't diagnosed with Alzheimer's Disease until 1994, the disease would have affected his performance during that year's race enough to alienate pretty much everyone. 1996 is, of course, impossible.
== Examples of the Reagan Range ==
* What if Gordon Banks Had Played? by Anthony Wells has Governor Reagan narrowly edge out President Ford in the 1976 primaries and defeat Ted Kennedy in the election. In 1980, Reagan intervenes to restore democracy to a Great Britain that is barreling towards authoritarianism under the tyrannical premiership of Enoch Powell and his inner sanctum.
* The small bit of alternate history in Stephen King's 2011 novel 11/22/63, in which a time-traveling high school teacher saves JFK from assassination, has Reagan absolutely obliterate Hubert Humphrey in the 1972 election, carrying all 50 states. By this point, however, butterflies have led to the rise of Islamic terrorism decades earlier than in OTL, and in the words of one character, Reagan "could speechify like a motherfucker, but he didn't understand a thing about radical Islam". This leads to some thoroughly unpleasant things, including nuclear strikes by terrorists, one of which turns the Gulf of Mexico into "dead soup".
* New Deal Coalition Retained sees Reagan elected in 1976 over Henry M. Jackson, and reelected in 1980 over George McGovern and John J. McKeithen in a truly enormous landslide.
* No Southern Strategy plays with this trope: Reagan wins the primary in 1968 (and picks Edward Brooke as his running mate, placing the first ever African-American on a major party ticket), but loses in the general to Hubert Humphrey.
* Thaxted by Sydney Webb also plays with it, having Reagan win the 1972 primary, but losing to Bobby Kennedy in the general,