Democrats are weaving together a string of anecdotes about Mitt Romney to argue he lacks compassion, and the former Massachusetts governor might have to fight back using something he doesn’t like to talk about — his Mormon religion.

The tales about Romney range from the trivial to the traumatic, from the political to the personal. But the Obama campaign’s hope is that they create a synergistic, decidedly negative portrait of a candidate who is still largely unknown to many voters.

Romney’s sins, according to Democrats: He once strapped his dog, Seamus, to the roof of his car during a family vacation; he reportedly bullied a fellow high school student who was gay; and he helped ship jobs overseas while working at the investment firm Bain Capital.

They’ve also pointed to various Romney statements, such as that he “likes to fire people” and he’s “not concerned about the very poor,” to suggest a political myopia for a man who wants to be president.

The veracity of the stories and statements has been debated but, whatever their merit, all are intended to buttress the notion that Romney is missing a compassion gene.

Will it work?

So far, it looks like Democrats are barking up the right tree.

An AP poll this month showed that voters thought President Obama understood their problems better than Romney, 51 percent to 33. The most recent NBC/Wall Street Journal poll showed Obama beating Romney by 30 points on “caring about average people” and 29 points on “being compassionate enough to understand average people.”

And in Quinnipiac’s most recent poll, only 44 percent said Romney cared about the problems and needs of people like them, while 57 percent said the same about Obama.

So the evidence is clear: A compassion gap exists, and Romney needs to figure out how to cut into it.

There’s no shortage of anecdotes about Romney’s compassion and kindness on a personal level — many of them recounted in Michael Kranish and Scott Helman’s biography, The Real Romney. But there’s a distinct danger in regaling voters with these stories. Many of Romney’s acts of kindness were toward Mormon families, and so any discussion about those tales also raises the prospect of a less welcome discussion of Romney’s religion.

Romney himself has made it clear that he’s not interested in veering into theological discussions during the campaign, and it’s not hard to see why. Mormon doctrine remains a mystery to many Americans, and the Romney campaign would rather litigate Obama’s record, not Joseph Smith’s.

Thus, it’s easy to see why the campaign might be reluctant to talk about Romney’s many acts of kindness. That hesitation seems to be born nearly entirely of religion and not a sense of personal modesty, as the following story suggests.

In 1996, the teenage daughter of one of Romney’s co-workers at Bain Capital went missing for three days. When the police struggled to find her, Romney temporarily shut down his Boston-based company and flew both himself and his employees to New York City to help find the girl, who was eventually located.

It’s a moving tale of compassion, but also politically instructive. When he ran for president in 2008, Romney cut a TV ad telling the story, and then four years later, a super-PAC supporting him, Restore Our Future, released a nearly identical version of the spot. As for Romney himself, The Associated Press notes that, although he hasn’t mentioned it frequently on the campaign trail, he has occasionally recounted the story.

What’s particularly noteworthy is why Romney and his allies would choose to focus on this particular tale of compassion over others, and the answer might very well be that it wasn’t related to Romney’s religion.

That’s not the only time Romney’s campaign has chosen to highlight a non-religious example of his compassion. After the allegation of Romney’s high-school bullying broke, one of his advisers went on TV to defend Romney as “deeply compassionate” and, oddly, pointed to a presidential debate during which Romney tried to help a stumbling Rick Perry collect his thoughts.

It was striking that the campaign chose to trot out that moment to defend the candidate’s “kind impulses,” and not the myriad stories detailing his charitable work with the Mormon Church.

Since delivering an address on Mormonism in his 2008 run, Romney has assiduously avoided a deeper personal discussion of his faith. Some pundits have suggested that he open up about the subject, and although that carries risks, it also brings opportunities. If Romney and his campaign were more comfortable talking about faith, they could also stress the compassionate anecdotes.

So far, it doesn’t look like Romney’s interested in indulging in a deeper look at either his faith or his role in the church, but the compassion gap between him and Obama is massive, and, at some point, Romney might put voters’ sympathy for religious tolerance to the test.