Show me a time when Mainline Protestants are not voting to the right of Catholics.
On what issue? Catholics have always been ferociously anti-communist forever. And voting Republican does not mean voting right on issues. Cathoilics supported the Vietnam War under Kennedy , Johnson, and Nixon. They supported Nixon over McGovern in 1972. Until 1976, the Republican Party was the pro-abortion party. Gerald Ford was more pro-abortion than Carter.