What is a Republican? And a Democrat?

There are only two major political parties in the US; the Republicans & the Democrats. A representative from one or other party has won every presidential election since 1852. The above presentation briefly describes the key differences between them.

How did they get the names Republican and Democrat?
This gets very confusing!

The Federalist Party of Alexander Hamilton  was opposed by Thomas Jefferson who formed an opposition party in 1792. Jefferson's  party developed into the Democratic-Republican Party (1798) and was the forerunner of the modern Democratic Party.

The  modern Republican Party was founded in the 1850s and  key features included opposition to slavery and a support base in the northern states. Abraham Lincoln was a Republican, while the pro-slavery southern states were largely Democrat.

Broadly speaking, the Democratic Party is left-of-center and the Republican Party right-of-center As the 2000 Presidential Election spectacularly proved, the American electorate is divided into these two camps. On one side are the Democrat-voting blue states, located primarily on the coasts (California and New York, for example) and in the north-east. They are opposed by the Republican red states of the so-called fly-over heartland and the south.
Registered voters in 2004
Who supports which party? Why?
The core voters of a party are known as the base. On the Democrat side the base is largely consists of trade unionists and various interest groups defined by race or social outlook. For red state Republicans the unifying issues tend to be pro-life (anti abortion), anti gun control and pro small government. Democrats often describe themselves as progressives and Republicans as values voters.

What is a filibuster?