White evangelical Christians and white Catholics appear to be the key swing groups in this unusual presidential election. Although very different in some ways, both groups have responded to a Clinton-Trump race with even less enthusiasm than the electorate as a whole. Let's consider white evangelicals first. Strongly oriented toward Republican presidential candidates since the 1980's, this group views Trump's personal story and sometimes crude behavior with considerable disquiet. The idea of a GOP presidential nominee who is thrice-married, promotes casinos named for him, and seemingly knows little about the Bible turns them off. So, too, do Trump's hurtful comments about rivals and their supporters, his lack of contrition about that behavior, and his manifest lack of humility. Actively repelled by Hillary Clinton's candidacy, for her liberal stands on such hot-button issues as abortion and marriage equality for gays and lesbians, and her apologies for her husband's infidelity, white evangelicals find themselves without an attractive major-party candidate. Some polls suggest that lately they have come around to the idea of voting for Trump thanks to his promise to appoint socially conservative Supreme Court justices, and his tough line on fighting terrorism. Even so, that drift toward Trump doesn't, as yet, signal firm commitment to his candidacy. Should he turn off that kind of voter with a boorish or overly negative performance in presidential debate two and/or three, that tepid support may evaporate. That matters greatly to Trump, for without a strong turnout on his behalf from white evangelicals, the polls suggest that he cannot win.
White Catholic voters appear more committed to voting for someone, but less sure which candidate to back. They share many of the same objections to both candidates as white evangelicals do, but without the strongly Republican orientation. White Catholics tend to be economic populists and moral traditionalists. Since the 1970's they have been a true swing group of voters. When Bill Clinton ran for president the first time, he ultimately won only a plurality of white Catholics in a three-way contest (and a bare majority of all Catholics), but their votes proved crucial in the pivotal Midwest. In what is much more of a two-person contest this time, given the much lesser strength of the minor party candidates in 2016 than Ross Perot's in 1992, Hillary Clinton is doing somewhat better among white Catholics than her husband did then. That support is fluid, however, and could shift depending on how the final month of the campaign plays out. Roughly one in five voters between Pittsburgh and the prairies is Catholic, and Hillary Clinton needs to win a majority of that group to claim the White House. Very strong support from Latino/a Catholics (thanks to Trump's provocative stance on immigration) promises to help in that regard, but that alone is not enough.
The clearest sign that both Trump and Clinton understand these demographic factors can be seen in their running mate choices. Trump picked Mike Pence, who grew up Catholic and now attends an evangelical megachurch, giving him appeal both to Catholics and white evangelicals. Clinton tapped Virginia Senator Tim Kaine, a Catholic who speaks good Spanish from a state with a lot of white evangelicals, as her vice presidential candidate. Last night's vice presidential debate was of special interest to both white evangelicals and Catholics, who no doubt listened carefully to two politicians they are inclined to respect for clues about what a Clinton or Trump victory would likely mean. If it seems, once the survey results are in and fully analyzed, that either Pence or Kaine actually won the debate, that could help move their respective tickets a bit closer to victory.