Fascinating historical point, Ivan. Thanks for that post. Were the party to fracture, I wonder what blocs would go where, or if certain elements would simply be discarded, as you mentioned.
I don't believe the Republican party will fracture. If it was going to do so, it would have occurred in 1880, or again in 1884 when the "Mugwumps" refused to support James G. Blaine. Or indeed again in 1912, when Roosevelt created the Bull Moose Party, or again in 1976 when Reagan was asked to go third party. The system supports two parties; in order for a new party to form, one has to die. The Republican Party was born out of a cross party consensus - it attracted Whigs, anti-slavery Democrats and members of the Free Soil Party. I see nothing like that at present.
Regards, Ivan