When looking back at previous primary elections, sources tend to differ when listing which "major" candidates participated in each race. Often, there will be disagreements over who should and should not be considered to have been a notable candidate, with many references generally listing different numbers of candidates when analyzing historical primary races. Because of this, I thought it would be interesting to develop some sort of a more defined set of criteria in order to better determine exactly how many "major" candidates ran in each presidential race ever since the modern primary system began in 1972.
I will now explain my reasoning behind each of the above criteria:
Criterion 1 - While 20% of the nationwide primary vote may seem like a rather high threshold, one must take into account primary elections in which incumbent presidents are faced with severely depressed primary voter turnout, hence allowing insurgent and perennial candidates to gain inordinate amounts of percent support. For example, while both Bill Clinton and Barack Obama lost more than 10% of the Democratic Party nationwide primary vote during their respective reelection campaigns in 1996 and 2012, neither of the aforementioned presidents actually faced a relevant primary challenger, hence necessitating the 20% nationwide support requirement. However, Criterion 1 does still allow genuinely popular primary candidates who ran against incumbent presidents to gain major-candidate status, most notably Pat Buchanan in 1992.
Criterion 2 - Though this criterion does not specifically award major-candidate status to any candidate who would not have achieved said status otherwise, the traditional importance of "winning states" in the primary election process allows this criterion to maintain its inclusion. Furthermore, this criterion could easily become relevant in future primary election scenarios in which a primary challenger bests an incumbent president in at least one statewide contest but fails to meet Criteria 1, 3, and 4. Prominent examples of Criterion 2 nearly being relevant to awarding major-candidate status include Pat Buchanan in 1992 and John Wolfe in 2012.
Criterion 3 - This criterion is likely the most relevant in awarding major-candidate status to candidates unable to meet the political office requirement of Criterion 4. Candidates given major-candidate status solely due to the inclusion of Criterion 3 include Jesse Jackson (D-1984), Alexander Haig (R-1988), Alan Keyes (R-1996), Morry Taylor (R-1996), Alan Keyes (R-2000), Gary Bauer (R-2000), Al Sharpton (D-2004), Wesley Clark (D-2004), Rudy Giuliani (R-2008), Herman Cain (R-2012), Carly Fiorina (R-2016), and Ben Carson (R-2016).
Criterion 4 - This criterion, while one of the most benign, is also the most effective in awarding major-candidate status, particularly to prominent incumbent or former officeholders who ended their presidential campaigns before winning the plurality of the vote in a statewide contest or 20% of the nationwide primary vote. Most candidates are awarded major-candidate status due to this criterion.
While Criteria 3 and 4 are clearly the most relevant in deciding who should and should not be considered "major" candidates, Criteria 1 and 2 are still relevant in both their traditional importance to the primary election process and their potential to provide major-candidate status to those who would not have received it otherwise in future elections. Overall, while not perfect, this set of criteria does seem to by far be the most accurate way to determine which historical presidential candidates should be considered technically relevant to their respective presidential races.
TL;DR - I've developed a set of criteria to determine which presidential candidates should have been considered "major candidates" in every primary election since 1972. The criteria are in the quote box.
I will start posting the actual candidate results for each election in a bit.
Thoughts?