Same reason they opposed Civil Rights for African Americans in the 60s and 70s
I don't know what shovel-faced bum taught you your freeping history, but you really need to know that the Republican Party was the party that freed the slaves, and the Democrats were the party that opposed all that nonsense, right down to George Wallace and Bull Connor (Democrats) who were viciously opposed to the Civil Rights Bill. Getting these facts "erased" from American history has been a major triumph of the Democrats, who were also the party of the KKK Supreme Lizard Byrd, who served as a Democrat for about a million years before collapsing of hypocrisy.
How the freeping Democrats managed to convince blacks to become Democrats is one of the great untold stories of our time, and fortunately, it is all falling apart, right now, as blacks and gays suddenly realize that they are FREE. With equal rights to life, liberty, and the pursuit of happiness.
Anyway, we will all know a lot more on November 2nd.
"I have voted!! I hope you don't!!

"