1960
You could argue in this election that it was Richard Nixon's "turn," as he was the sitting Vice President. But arguing that the Republicans have put too much stock in the Vice Presidency in preparing a candidate for his "turn" obscures the fact that, like the position of Chancellor of the Exchequer in England, the VP slot has
ALWAYS been a prime predictor of Presidential fiber. This has been true since Vice President John Adams succeeded George Washington. What's more, it's a trend even more prevalent in Democratic primaries; during the past twelve primary cycles, two times the winner has been the sitting Vice President (Hubert Humphrey in 1968, Al Gore in 2000), and once it has been the Vice President immediately previous (Walter Mondale in 1984). So if nominating Vice Presidents is a manifestation of "turn," it's one that affects Democrats as much as Republicans.
In any event, despite his status as Vice President, nobody really liked Nixon, and he had a powerful populist opponent in Nelson Rockefeller. However, Rockefeller's avowed liberalism was far too left-wing for the Republican establishment, who eventually backed Nixon after a hard-fought race. This wasn't a matter of "turn," it was a matter of the establishment rallying around the obvious candidate because they were afraid of the radical reformer. Nixon won, but Rockefeller got to dictate the party platform anyway in the Fifth Avenue Compact.
1964
The previous Vice President, Richard Nixon, was off in the wilderness somewhere; the Speaker of the House and Senate Majority Leader were both Democrats. So the only politician with a claim to this "turn" was Nelson Rockefeller, who had run for and lost the nomination four years earlier. Certainly he had more claim to the nomination than the contrarian conservative Senator from Arizona, Barry Goldwater, right?
Wrong. Goldwater's narrow victory over Rockefeller -- in a race in which there was no significant establishment presence, as both candidates were unacceptable to the mainstream wing of the party -- stands in direct opposition to the concept of "turn."
1968
After Goldwater lost to Lyndon Johnson by a record margin in 1964, it was REALLY Rockefeller's "turn" this time. Nevertheless, Richard Nixon came back from the wilderness to claim a second chance at the Presidency that he wasn't entitled to under any reasonable concept of "turn (he hadn't even held political office in eight years). The resulting nomination played out as a repeat of 1960, with the party establishment again backing Nixon over the overly liberal Rockefeller. This was a clear instance of establishment trumping "turn." Ronald Reagan came in a distant third.
1972
Not applicable, as Nixon was the sitting President and had no significant primary opposition.
1976
In the closest primary race in the history of binding Presidential primaries, President Gerald Ford narrowly defeated Ronald Reagan. Reagan didn't lose because of a need to "wait his turn," he lost because he was running against a sitting President. Keep in mind that no Democratic President has lost renomination during the same period, though Jimmy Carter had to beat back a stiff challenge from Ted Kennedy in 1980.) In order to pacify the right-wing Reagan supporters, Ford axed his Vice President, Nelson Rockefeller, replacing him with conservative Senator Bob Dole.
1980
Ronald Reagan's victory in 1980 is routinely billed as an instance of taking his "turn," as he had run twice before and had firmly established himself as next in line with his narrow 1976 loss. This analysis ignores both Reagan's prodigious campaign skills, which were clearly superior to those of his lackluster opponents, and the fact that he was not the only candidate with a claim to this "turn." Bob Dole, who had been Ford's VP nominee in 1976, also ran for President in 1980, but flopped early and didn't even threaten to win a single primary. In a race dominated by "turn," the primary would have become a dogfight between Reagan and Dole; the fact that Reagan's main opponents were instead a tight-lipped former CIA director named George H. W. Bush and the moderate John Anderson, who later bolted the party to run against Reagan as an Independent, is very telling.
1984
Not applicable, as Reagan was the sitting President and had no significant primary opposition.
1988
Another year where "turn" is regularly invoked, another instance where George H. W. Bush won the nomination because, as sitting Vice President, he was the natural choice for the establishment. Despite this, Bob Dole put up a strong showing as another establishment candidate, and Pat Robertson gave Bush quite a scare by finishing ahead of him in Iowa. Jack Kemp put in an ineffectual performance as well. Bush won and tapped Dan Quayle as his running mate.
1992
As the sitting President, Bush was challenged with surprising effect by ultraconservative Pat Robertson. Bush's less-than-convincing victory should not be construed as an incidence of "turn," as a sitting President is always entitled to renomination in either party.
1996
This election is the one instance in which "turn" can be said to have played a major part in the outcome. Bob Dole had run twice before, done well in 1988, had been a vice-presidential nominee in 1976, and was the new Senate Majority Leader. His main rival for party power, House Speaker Newt Gingrich, passed on the race, as did the other man with a legitimate claim to this "turn," former Vice President Dan Quayle (who could have invoked the Mondale 1984 rule and run four years after his ticket lost). In addition to Dole's prominence in the party, he enjoyed the kind of insider influence no nominee had enjoyed since Lyndon Johnson; with his years in Senate leadership, he controlled nearly the levers of his party's power.
Still, Dole's victory was far from assured, as he received stiff challenges from Pat Buchanan (who had some claim to the "turn" himself after his strong 1992 showing), Steve Forbes, Lamar Alexander, and Phil Gramm. Perhaps the stiffest challenge came from Gramm; though he was out by the first caucus, his wins in early Southern straw polls set off a dogfight for establishment support between the two, which was settled only when Dole ran attack ads against Gramm that accused the Texas Senator of, ironically, dirty tricks.
2000
The 2000 election is the most elegant disproof of the concept of "turn," as it was in no realistic sense George W. Bush's "turn," with his scant six years in politics. Of those who had a legitimate claim to this "turn," Kemp and Gramm were too old, Buchanan and Forbes were too conservative, Senate Majority Leader Trent Lott was uninterested, and Newt Gingrich was in disgrace. However, it's worth noting that two candidates who had a very strong claim to "turn" -- Dan Quayle (stretching out the Mondale 1984 rule for an extra four years) and Lamar Alexander -- actually DID run in 2000, and did so badly in early straw polls that they dropped out well before the first caucus. The party establishment's complete support of Bush (to the tune of $65 million raised in 1999) so completely trumped "turn" that Bush's major competitor was a maverick senator named John McCain, who didn't have legitimate "turn" standing either.
2004
Not applicable, as Bush was the sitting President and had no significant primary opposition.
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During the past twelve election cycles -- beginning even before the dominance of binding primaries -- there has only been one instance where the Republicans nominated a Presidential candidate simply because it was his "turn." Rather, with the notable exception of 1964 (when no truly "establishment" candidate was running), successful Republican aspirants have achieved the nomination through a combination of strong establishment support and adequate popular appeal. Just as with any party, the Republicans can nominate a candidate whose "turn" it is at a moment of particular demoralization (and Democrats can do this too -- think of Freddy Ferrer's ludicrous nomination for New York City Mayor in 2006); but attempting to win the nomination by assiduously courting one's "turn," as John McCain has been doing, is certain to backfire.
It is not McCain's "turn" to run in 2008, nor is it any other candidate's. Instead, it will be the turn of the candidate who successfully courts the Republican establishment while remaining relevant to the GOP rank-and-file. Predicting the result through this lens is meaningful; predicting it through the myth of "turn" is meaningless.