So I had mentioned a few days back that Obama's election was a transforming moment for the GOP, a catalyst away from Reagan-style Movement Conservatism to Trump Style White Nationalism/Alt-Right. I wanted to illustrate the other watershed moments for the two parties over the years:
Jefferson's Legacy:
Catalyst 1: Expansion of the vote to all White Men, ~1824. This ended the Democratic Republican party with its Libertarian ideology to the early Democrats, who were Populist.
Catalyst 2: Texas Independence, 1835. This shifts the Democrats from a Populist party to a Nationalist one as the party re-orients towards western expansion. Jackson's focus on Indian Removal also assists with this shift.
Catalyst 3: Fugitive Slave Act, 1850. This shifts the Democrats towards being pro-slavery as their defining issue, changing Nationalism to American (in the broader New World sense) style Conservatism (so similar to the kind of Conservative parties you saw in Latin America at the time)
Catalyst 4: Hayes-Tilden Compromise, 1876. This ended reconstruction and put race issues on the back burner in the US for 80 years. For the Democrats, this meant giving up the ghost of American Conservatism and switching to an economic issues focus. They became an anti-industrial or sort of Luddite Conservative party.
Catalyst 5: The silver boom of circa 1890. This shifted the party from Luddite Conservative back to Populist on the back of growing urban-rural inequality and a focus on getting stuff back for the rural white majority.
Catalyst 6: Treaty of Versailles, 1919. This is where globalist ideals were elevated to the top of the Democratic party by Woodrow Wilson, which cut against the nativist flank of the party and pushed the party to a sort of Left Populist position, helped by the growth of labor unions in the party ranks through the early 1900s.
Catalyst 7: Truman's Fair Deal, especially integrating the US military, circa 1950. This is when you start to see the left-wing ideas really take over the party and pushes the party to Social Democratic, despite the huge numbers of Southern Dems contributing to the overall party still.
Catalyst 8: Stagflation, circa 1975. This is when the social democratic economic policies of the Dems suffered a crisis and Keynesian economics was discredited. Followed by the electoral drubbings of 1980 and 1984, this pushed the party from Social Democratic to Third Way, both economically "liberal" and socially liberal.
Catalyst 9: Grassroots Activism of the 2010s. I think Occupy Wall Street and Black Lives Matter are what's pushing the party to the left, dropping Third Way policies in favor of Progressive ideals. Obviously inertia is a big thing and the party is not a monolith, but it's turned a corner and those two grassroots movements are the cause.
Adams's Legacy:
Catalyst 1: Expansion of the vote to all White Men, ~1824. The Federalist party had already collapsed, but this allowed it to be replaced by the National Republicans. The Federalists were based around European-style Authoritarianism, the National Republicans held a more popular view, Mercantilism.
Catalyst 2: Panic of 1837. This first major economic crisis faced by the US helped to discredit the fiscal and monetary policies of the Jacksonian Democrats and galvanized the opposition around new economic philosophies. The National Republicans faded and were replaced by the Whigs. 18th-century style Mercantilism was replaced by 19th century Capitalism.
Catalyst 3: Fugitive Slave Act, 1850. This again polarized the country around the slavery. The Whigs had pro-slave elements and collapsed because of the polarization. Anti-slave Whigs aligned with Free Soilers formerly aligned with the Democrats and made the Republican party. The crisis of slavery turned Capitalism into Classical Liberalism.
Catalyst 4: Hayes-Tilden Compromise, 1876. Again, putting race issues on the back burner meant that the more radical ideals of the Republicans at the time faded away and they refocused on economic issues, going from Classical Liberalism to Corporatism.
Catalyst 5: Sherman Antitrust Act, 1890. The massive inequalities of the Gilded Age caused a Progressive sentiment to rise up in the urban and suburban voting base for the GOP at the time and pushed it into a Progressive posture for a while (not left-progressive like the Dems today, a more Scientific Progressivism focused literally on the idea of human progress).
Catalyst 6: The First Red Scare, ~1920. The first red scare in the wake of the Bolshevik Revolution and backlash to the Versailles Treaty stumped the Progressive elements of the GOP and put it back to a Corporatist party.
Catalyst 7: The Second Red Scare, ~1950. The second Red Scare during the Cold War pushed socially conservative people towards the Republican party and changed it from Corporatist to Conservative (but a sort of Nixon-style conservatism which was NOT the reactionary movement that followed).
Catalyst 8: The Culture Wars, ~1975. For this I'd point specifically to two Supreme Court Cases, Roe v Wade and Bob Jones University. Bob Jones was the last vestige of legal segregation, an attempt by a Christian university to claim a legal right to bar black people under first amendment religious grounds which was struck down. Roe helped to take its place, with the right-wing movement realizing that the segregation battle was finally lost, they switched to other forms of social and religious agitation. Conservatism became Movement Conservatism, a more activist and reactionary form.
Catalyst 9: Barack Obama's election, 2009. To the GOP, this was a sign that they had lost the Culture Wars and their worst fears were realized (at least to them). This radicalized the party, combined with the toxic stew of right wing media, and pushed the party from Movement Conservatism and towards White Nationalism and the alt-right.
So that's my theory on how we got here.