There was a time

 There was a time in American life when it was considered bad manners to talk about politics or religion at the dinner table. There were good reasons for that — those subjects tend to get people upset and angry and that's always rough on digestion. But I doubt it was ever something that was practiced much because when people aren't gossiping or talking about work, politics and religion are the most likely topics whether we like it or not. Still, I don't think the merging of religion into partisan politics has ever been quite as thorough as it's been in the past 40 years or so. Sure you can go back in history and see many examples of religious leaders being politically influential from Cotton Mather to Brigham Young to Martin Luther King Jr. And various religious movements have been deeply involved in social reforms forever. But the emergence of the Christian Right under the auspices of organizations like the Moral Majority led by the Reverend Jerry Fallwell and Pat Robertson's Christian Coalition was explicitly formed as a faction of the Republican Party for the purpose of electing officials who would carry out their political agenda. That was unusual and it has been wildly successful.

-Heather Digby Parton in Salon.com