Political scientist Philip Wallach has argued that Trump's Republican Party is taking the path to extinction followed by the Whig party in the early 1850s. The Whigs had been one of the two major parties--along with the Democrats--since the 1830s. In 1848, the Whigs' presidential candidate was General Zachary Taylor, who had no political history in the party at all. Although he won the election, this began a period of intraparty factionalism that brought the demise of the Whigs and the rise of the Republican Party, founded in 1854, as the new second party.
I can agree with Wallach that if the Republican Party continues to embrace Trump's illiberal populism even after his defeat, then the party will become a permanent minority party, or it will disappear altogether. But if American presidential elections show an evolutionary process of survival of the fittest as parties compete in the political marketplace, then both the Democrat and Republican parties have shown adaptive fitness in surviving electoral defeats. The Republican Party can survive Trump's defeat, and even losing control of both Houses of Congress, but only if the Party adapts by rejecting the illiberal populism of Trump and returning to the values of the Lockean liberal Enlightenment that lies at the foundation of the American political tradition.
The primacy of the liberal Enlightenment for American politics was affirmed by Barack Obama in his Farewell Speech delivered in Chicago on January 10, 2017. He claimed that what makes America exceptional is its commitment to the Lockean principles of the Declaration of Independence--"the conviction that we are all created equal, endowed by our Creator with certain unalienable rights, among them life, liberty, and the pursuit of happiness." He saw this "essential spirit of this country" as established by the Founders as "born of the Enlightenment"--"a faith in reason, and enterprise, and the primacy of right over might."
Obama left office with an approval rating of 58%, while Trump entered his office with a 40% rating--the lowest ever for an incoming President--and in his first 7 months in office, that approval rating dropped to 34%--well below the average for any new president. The day after Trump's inauguration, the Women's Marches against Trump brought out over 2 million people across the country--673 marches in all 50 states--which was probably the largest single-day mass protest demonstration in American history. That this unpopularity had something to do with his illiberal policies became clear in the mid-term elections of 2018. Trump turned these elections into a referendum on his two signature policies--trade wars and anti-immigration--and these policies were so unpopular with the voters that the Democrats had their biggest gain in a midterm election since 1974, in the aftermath of Watergate and Nixon's resignation.
It is true that Trump's policies of protectionist tariffs and immigration restrictions have a long history in the Republican Party. Republicans supported the Immigration Act of 1924, which put severely restrictive quotas on immigrants from Southern and Eastern Europe and prohibited immigration from Asia. Republicans also supported the Smoot-Hawley Tariff Act of 1930, which set the second highest tariff levels in American history. But it became clear that the Smoot-Hawley tariffs worsened the effects of the Great Depression, which was one reason for the move to promote free trade agreements after World War II. And the Immigration and Naturalization Act of 1965 eliminated discrimination against ethnic groups outside of Northwestern Europe. In these ways, the Republican Party recognized the wisdom of John Locke's liberal argument for open borders and free trade. Trump has turned the party against the Lockean liberal position.
If the Republican Party is to survive Trump's defeat, it will have to engage in the sort of adaptive change in its policies and demographic profile necessary for success in the two-party system that evolved in the United States in the middle of the 19th century. The American Founders did not like the idea of political parties, because they saw them as advancing factional special interests contrary to the public good. In George Washington's Farewell Address, he warned his audience "in the most solemn manner against the baneful effects of the spirit of party generally." The U.S. Constitution says nothing about parties, and Richard Hofstadter (in The Idea of a Party System) identified it as "a Constitution against parties."
Nevertheless, the conflicts between Alexander Hamilton and Thomas Jefferson in Washington's administration led to the first two-party system--with Hamilton leading the Federalists and Jefferson leading the Republicans. And yet this seemed to confirm the fear that party competition was corrupting, because each party assumed that winning required the total destruction of the other party--there was no idea that the party in power could tolerate the party out of power as the "loyal opposition."
It was not until the early 1830s that the modern party system was invented in the United States as part of what some scholars have called the "open access order" (Douglass North et al., Violence and Social Orders). (I have written about that in a previous post.) An open access order allows most citizens to have open entry to economic, social, and political organizations that the state will support. These organizations are free to compete with one another in peaceful ways. Throughout most of human history since the Neolithic, organizations supported by the state were elite privileges that were not open to most people.
In 1828, the Democratic Party arose under the leadership of Andrew Jackson. Then in the 1830s, in opposition to Jackson's Democrats, the Whig party emerged under the leadership of Henry Clay. The Democrats and the Whigs competed as the two major parties. Since then, the United States has had a two-party system in which third parties have not endured for very long because the electoral rule of "winner-take-all" discourages third parties. This has created an electoral system of free competition through evolution by "creative destruction" (as Joseph Schumpeter called it): in party competition, any group is free to form a party organization, and those parties that succeed through innovative policies and coalitional strategies in the political marketplace gain power, while those that fail are forced to change, or they are extinguished.
By that standard, the Democratic Party has been a great success. It has endured for 187 years, which makes it the oldest political party in the world. The Whig party lasted for only about 22 years. They were replaced in 1854 by the Republican Party, which has endured for 166 years, making it the third oldest party in the world. The Conservative party of Great Britain is older--founded in 1834.
The great age and durability of the Democratic and Republican parties shows their evolutionary fitness for survival. They have often faced challenging electoral defeats that appeared insurmountable at the time. But they have developed adaptive responses to those challenges by changing their policies and socioeconomic demographics to exploit opportunities in the political marketplace.
But while both parties have had to change--changing their policies and changing their constituencies--in order to adapt to a competitive political marketplace, each party has a core character that has endured. As Michael Barone has said, the Democratic Party has always been "a coalition of out-groups that, when held together, can win majorities," and the Republican Party has always centered on "a core constituency of people who are regarded by themselves and others as typical Americans, but who are not by themselves a majority of the electorate."
Despite these differences in their core character, however, both parties have to agree in their Lockean liberalism, because America is inherently a Lockean liberal society. Louis Hartz (in The Liberal Tradition in America) was right about that: Lockean liberalism is America's one and only political philosophy. That's why no truly illiberal political party has ever been very successful in the United States. And that's why the survival of the Republic Party will depend on its rejection of Trump's illiberal populism.