True, Trump has finally rallied the crucial white evangelical Christian base of the GOP to his side. But he still has outspoken detractors among prominent Christian conservatives, and he is viewed with ambivalence and even deep suspicion by many Jewish, Muslim and Mormon voters and members of other minority faiths.
And it's not just smaller religious groups: a Pew Research Center survey released this month showed the overall "God gap" shrinking significantly, with registered voters who attend religious services at least weekly leaning to Trump by a 49 percent to 45 percent margin over Clinton. That is far smaller than the 55-40 advantage that Republican Mitt Romney held over President Barack Obama at the same point in 2012.
With the key Catholic swing voter, Clinton actually leads Trump by a whopping 19-point margin among weekly Mass-goers, whereas Romney led Obama by 3 points among that same group — a 22-point shift.
And with Clinton's selection of U.S. Sen. Tim Kaine, D-Va., as her running mate — a Jesuit-educated Catholic who served as a missionary in Honduras — the Democratic nominee, a lifelong Methodist who can speak fluently about her faith, has a chance to widen the lead over Trump.
The big question now, however, is whether the Clinton campaign is equipped to exploit that opening, or if it wants to.
The campaign only hired a full-time faith outreach director earlier this month, and in the days leading up to Monday's opening of the Democratic National Convention, staffers were still scrambling to fill out a lineup of faith-friendly speakers and events to try to showcase their outreach to the media and a huge television audience.
"Hillary Clinton, and even the Democratic National Committee, have not been very active in pursuing the faith-based vote, nowhere even like what [the Obama campaign] did in 2012, which was nowhere like it was in 2008," said John Green, director of the Bliss Institute of Applied Politics at the University of Akron and a leading expert in religion and politics. "So there really has been a decline in that" effort.
Moreover, Trump has been divorced twice and has a history of vulgar behavior and switching positions on foundational issues to many believers — like abortion rights — while often struggling during the campaign to present a convincing witness of his Christian faith.
"The bar is lower than it's ever been for Democrats just to show they're not antagonistic to people of faith," said Michael Wear, an evangelical who worked on faith-based issues for the White House during Obama's first term and then directed faith outreach for the 2012 re-election campaign.
Wear, who writes on faith and politics and runs a consulting firm, will be on one of several "faith council" panels that the convention is hosting in Philadelphia.
"Hillary doesn't have to back down on principle one bit," said Wear. "She never has. The question is whether they choose to look at the faith community as a convenient foil or whether they are going to live up to the message of unity and togetherness of the campaign and actually engage in faith outreach."
In a sense, it's as if the Clinton campaign is making the old mistake of fighting the last war: Democrats have been so unsuccessful at attracting pew-sitters to the polls that many party officials and strategists have simply thrown in the towel and decided it's not worth the effort.
There are certainly strong arguments for not bothering too much with faith-based voters: As the electorate, like U.S. society, has become increasingly polarized, campaigns have become increasingly focused on turning out the base rather than trying to reach out to a shrinking center of persuadable voters.
For Trump and the Republicans that means trying to attract conservative Christians. For Clinton and the Democrats that has meant rallying the more secular voters and, in the process, often alienating faith-based voters.
Also, the Pew survey showed that even if Clinton isn't generating as much enthusiasm among religiously unaffiliated voters as Obama did in 2012, she is winning that demographic handily.