Anybody know what this means?

This paragraph cries out for conversion to plain English. It is terrible writing and not understandable by ordinary readers. If someone wants to rewrite it in plain English, please do so. Otherwise, it will be safe on this page.  

Baggett (2003) shows that Scalawags were for the most part long-time doubters or opponents of the Confederacy. He explains that along the continuum of "an 1860 antisecessionist Breckinridge supporter/1860 Bell or Douglas supporter/ 1860 antisecessionist / passive wartime unionist / peace party advocate / active wartime unionist / postwar Union party supporter" the farther an individual moved along this line the greater his chances of becoming a Republican (p. 271).