When Argentina redemocratized in 1983, its established political parties returned to contest elections. The Radical Civic Union (UCR), founded in 1891, emerged as a party of middle-class sharecroppers and small farmers threatened by the influx of European immigrants (Persello 2007).With the rise of Peronism in the 1940s, Argentina's oldest mass party formed the basis of the middle- and upper-class opposition to Juan Domingo Perón.

The Peronist party – officially called the Justicialist Party (PJ) – was the electoral vehicle founded by Perón in the 1940s. Proscribed on and off from openly competing in elections in the intervening decades, the party drew its electoral support from the rural poor and urban working classes (Lupu and Stokes 2009), developing corporatist and patronage ties to the Argentine labor movement. Its elites often relied on nationalist rhetoric promoting statist economic development, a “revolution in production,” and redistributive social justice (McGuire 1997).

To be sure, both the established Argentine parties were heterogeneous and, at times, inconsistent in these positions. Both also suffered various internal conflicts that sometimes fractured the party. For some scholars of Argentina, the distinction between the parties was one of rhetoric rather than ideology (Ostiguy 2009).

Rhetoric, ideology, and class appeal often went hand in hand, however. Whereas Radicals appealed to the upwardly mobile middle classes by promoting labor flexibility and strengthening democratic institutions (Gibson 1996), Peronism appealed to popular sectors with corporatism and nationalist rhetoric (Mora y Araujo 1995). In September 1986, nearly 50 percent of survey respondents named the UCR as “the party most bound to privileged sectors”; only 8 percent named the PJ.