For many years, it was far more common for Democrats to have brawling, bruising primary fights than Republicans.
The Democratic Party, after all, was a coalition of sometimes very different factions – African-Americans and Jews; labor and ethnic groups; factory workers and elegant, highly educated liberals in places like Ann Arbor.
They often had little in common except the fact that they were all more opposed to the Republicans.
Republicans, on the other hand, were more homogenous, more like an extended family that was largely business-oriented, largely white Protestant, and didn’t like fighting in public.
They even used to have what they called the Eleventh Commandment: “Thou shalt not speak ill of another Republican.” Well, times have changed.