The Republican Party today prides itself as the party of small government. But that wasn't always the case.
In the 1860s the Republican Party dominated the Northern States, and supported big government whereas the Democratic Party opposed the measure.
After the Civil War (liberal) Republicans granted protections for blacks to advance social justice (however little); Democrats opposed this progress. To be clear - during this time, conservative Democrats & liberal Republicans had a different view of political parties. The political parties switched as I'll explain later.
Fast forward to 1936, with the re-election of Democratic President FDR, who ran on the New Deal, which shifted Democrats from the party of small government to the party of expansive government, Southern Democrats revolted.
FDR's opponent Alf Landon opposed the expansion of federal powers to intrude on states' rights, which shifted the Republican Party to the party of small government.
Between the 1860s and 1936, the Democratic Party cemented its platform as the party of big government.
How did the switch happen?
In 1869, a man named Jennings Brian (D-NV) blurred party lines by emphasizing government's role in social justice. Politics played a significant role in Brian's approach after the Civil War New Western states created a new voting bloc.
Brian became the youngest person to be nominated for president at the age is 36 for the Democratic Party. To be honest - the political calculation set the stage for a new Democratic Party, which slowly pushed conservative Democrats to join the Republican Party.
Although the transition was slow, with each progressive piece of legislation, conservatives wanted no part of giving African-Americans the same rights as whites, which like today saw their power slipping away.