Rand Paul's is appealing to the Southern Democrats who became Republicans after Nixon changed the party strategy to be mean to black people ("Negros") in 1976. (see proof in links below)
I.E. THE REPUBLICANS OF TODAY HAVE NOTHING TO DO WITH FREEING SLAVES OR THE CIVIL RIGHTS MOVEMENT. THEY ARE THE DEMOCRATS WHO LOST AND THEN BECAME REPUBLICANS WHILE THE REPUBLICANS WHO HELPED THE BLACKS ARE NOW DEMOCRATS.
PROOFS
From http://en.wikipedia.org/wiki/Southern_Democrats
When Richard Nixon courted voters with his Southern Strategy, many Democrats became Republicans and the South became fertile ground for the GOP, which conversely was becoming more conservative as the Democrats were becoming more liberal. However, Democratic incumbents still held sway over voters in many states, especially those of the Deep South. Although Republicans won most presidential elections in Southern states starting in 1964, Democrats controlled nearly every Southern state legislature until the mid-1990s and had a moderate(although not huge) amount of members in state legislatures until 2010. In fact, until 2002, Democrats still had much control over Southern politics. It wasn't until the 1990s that Democratic control gradually collapsed, starting with the elections of 1994, in which Republicans gained control of both houses of Congress, through the rest of the decade. Republicans first dominated presidential elections in the South, then controlled Southern gubernatorial and U.S. Congress elections, then took control of elections to state legislatures and lastly came to control local offices in the South. Southern Democrats of today who vote for the Democratic ticket are mostly urban liberals. Rural residents tend to vote for the Republican ticket, although there are a sizable number of Conservative Democrats.
http://wiki.answers.com/Q/When_did_republicans_become_democrats_and_democrats_become_republicans "Republicans were always mostly in the Northern states ever since the Civil war. Also republicans favored a strong central government, hence Abraham Lincoln using the most federal power in history. The democratic party was always mostly in the southern states ever since the civil war because many Democrats supported slavery which was mostly in the South. Up unitl 1976 did democrats start to be mostly in the northern states and republicans in the southern states like it is today. They basically flip flopped demographics and ideas over 150 years."