I can't believe that anyone would compare the Democratic Party of today with the racists who abused civil rights workers 50 years ago. In President Lincoln's time, the Democrats were the party of rural voters. The Republicans were the party of the industrialized cities in the North, and supported the abolition of slavery.
Over the next hundred years there came a shift; the Democrats in the North supported labor unions and the end of segregation, but the Democrats in the South remained true to their segregationist roots; they became known as "Dixiecrats," and opposed the Democratic Party's liberal platforms.
These Dixiecrats included segregationists like Strom Thurmond who would, in the '60s and '70s, leave the Democrats and declare themselves Republicans. The Northern Democrats were glad to be rid of them, and the Republican Party warmly welcomed them.
Southern Republicans like Thurmond would continue to fight against integration. Their leadership in the Republican Party has been one of hypocrisy, civil rights violations and repression of the working class and poor.
Martin Luther King Jr., a Republican? Perhaps the Republicans of Lincoln's times, who are the Democrats of today, but never the Republican Party of 2008.