Protestants don’t vote democrat, they only voted democrat in 1932, 1936, and 1964
So they voted for the New Deal and Kennedy's successor. As to 1960, the election was close and stolen anyway.
But again, the real issue is not statistics but leadership. Both Protestant and the Catholics lose votes to the left, and they both lose their flock to those without a pronounceable religion; that is a shame, and that is happening because we don't have solid Protestant leaders any more that we have solid Catholic leaders.
Catholics voted for Obama, traditionally vote democrat (only straying 6 times), elected JFK with 80% of their vote and you choose to go after the Protestant vote of 1932, 1936, and 1964?
Catholics vote democrat, and soon, because of Catholic immigration, the Catholic vote will return to it’s normal place of NEVER going republican, all of America will vote like California.
Do you know how Catholic Hispanics that become Protestant vote? They vote more like Protestants.