One of the common generalizations about presidential elections is that incumbents win their political party's nomination if they seek it (David et al. 1960, 67; Keech and Matthews 1976, ch. 2; Epstein 1978, 178; Abramson et al. 1987). Though renomination challengers have not defeated an incumbent in over 100 years, several have generated significant attention and public support. (1) Most notable are Theodore Roosevelt's challenge to William H. Taft (1912), Ronald Reagan's challenge to Gerald Ford (1976), and Ted Kennedy's challenge to Jimmy Carter (1980). Lesser challenges include Hiram Johnson against Calvin Coolidge (1924), Joseph France against Herbert Hoover (1932), George Wallace against Lyndon Johnson (1964), and Pat Buchanan's challenge to George Bush (1992). Harry Truman also faced opposition to his nomination from southern Democrats in 1948, though no serious alternative emerged during the primaries. Truman (1952) and Johnson (1968) chose not to seek reelection, decisions that may have been influenced in part by the strength of other candidates in the New Hampshire primary (Keech and Matthews 1976, 45-51). (2) Since 1912, only Woodrow Wilson, Franklin D. Roosevelt (FDR), Dwight Eisenhower, Richard Nixon, Ronald Reagan, and Bill Clinton were essentially unchallenged in their renomination bids. While incumbents prevailed in every case, it is worth asking when and why candidates challenge incumbent presidents, and why some challenges attract more support than others.
Renomination challenges correlate strongly with the president's chances in the general election. In the last 100 years, five of the six most serious renomination challenges preceded the president's defeat in the general election. Presidents who faced no or only weak renomination challenges won reelection, typically by a landslide. Whether renomination challenges affect or reflect a president's chances in the general election is a matter of debate. Crotty and Jackson (1985, 205-06) characterize renomination challenges as increasing the likelihood of defeat in the general election. Mayer (1996b, 58-60) argues that presidents face renomination challenges when they are already likely to lose the general election. I address this debate by investigating the circumstances in which different kinds of candidates enter the race.
Despite their frequency and apparent significance, we know relatively little about when and why renomination challenges occur. Key (1964, 399) recognized the incidence of renomination challenges, but dismissed them as "revolts by noisy dissident factions within the parties." Though Keech and Matthews (1976, ch. 2) offered a detailed analysis, they excluded the most significant renomination challenges. (3) Abramson, Aldrich, and Rhode (1987) concluded that senators rarely challenge incumbents, but their theory does not explain why senators were the most frequent renomination challengers in the 20th century. (4) Crotty and Jackson (1985, 205-06) recognized that incumbents generally lose their reelection bids after facing a renomination challenge, but they did not address why incumbents are challenged. All of these studies discuss the difficulties of defeating an incumbent; none explain when and why presidents face renomination challenges in the first place.
Mayer (1996b, 46, 58-60) comes closest to providing an explanation when he observed that incumbents who are popular with their party members tend to be renominated with ease, while those who are not face a rocky reception. I agree with Mayer that renomination challenges depend on party members' evaluations of the incumbent's performance, but argue that renomination challenges are more complex. First, whether a challenger attracts support depends on party members' opinion of the president's performance and the characteristics and strategies of the candidates who pose an alternative to the president. Second, in contrast to Mayer (1996b), the model leads to the prediction that no, or only a weak candidate will challenge an incumbent when the president's party is considered likely to lose the general election. …