Today's Republican Party opposes big government.
It's culturally conservative.
Its demographic support is strongest among white voters, and it usually dominates elections in the South.
The party 2016 presidential nominee has been heavily criticized for inciting racial tensions.
But things weren't always this way.
Yet over the past 160 years or so, the party has undergone a remarkable transformation from the party of Abraham Lincoln to the party of Donald Trump.
To understand how the GOP got the way, you have to go back to when it first came into existence in 1854, just 7 years before the Civil War.
There are two parties at this point, the Whigs and the Democrats.
America is quickly expanding westward, and there's an intense debate over whether not the new states should permit slavery.
The Democratic Party with strong support in the South, has become increasingly pro-slavery.
